III. The drift: How the unthinkable became possible The Cold War was a dangerous game, but it was a game in which everyone knew and agreed upon the stakes and the rules. That is not the case today. The Western side believes it is playing a game where the rules are clear enough, the stakes relatively modest, and the competition easily winnable. The Russian side, however, sees a game where the rules can be rewritten on the fly, even the definition of war itself altered. For Russia, fearing a threat from the West it sees as imminent and existential, the stakes are unimaginably high, justifying virtually any action or gamble if it could deter defeat and, perhaps, lead to victory. Separately, the ever-paranoid Kremlin believes that the West is playing the same game in Ukraine. Western support for Ukraine's government and efforts to broker a ceasefire to the war there, Moscow believes, are really a plot to encircle Russia with hostile puppet states and to rob Russia of its rightful sphere of influence. Repeated Russian warnings that it would go to war to defend its perceived interests in Ukraine, potentially even nuclear war, are dismissed in most Western capitals as bluffing, mere rhetoric. Western leaders view these threats through Western eyes, in which impoverished Ukraine would never be worth risking a major war. In Russian eyes, Ukraine looks much more important: an extension of Russian heritage that is sacrosanct and, as the final remaining component of the empire, a strategic loss that would unacceptably weaken Russian strength and thus Russian security. Both side are gambling and guessing in the absence of a clear understanding of what the other side truly intends, how it will act, what will and will not trigger the invisible triplines that would send us careening into war. Today's tensions bear far more similarity to the period before World War I During the Cold War, the comparably matched Western and Soviet blocs prepared for war but also made sure that war never came. They locked Europe in a tense but stable balance of power; that balance is gone. They set clear red lines and vowed to defend them at all costs. Today, those red lines are murky and ill-defined. Neither side is sure where they lie or what really happens if they are crossed. No one can say for sure what would trigger war. That is why, analysts will tell you, today's tensions bear far more similarity to the period before World War I: an unstable power balance, belligerence over peripheral conflicts, entangling military commitments, disputes over the future of the European order, and dangerous uncertainty about what actions will and will not force the other party into conflict. Today's Russia, once more the strongest nation in Europe and yet weaker than its collective enemies, calls to mind the turn-of-the-century German Empire, which Henry Kissinger described as "too big for Europe, but too small for the world." Now, as then, a rising power, propelled by nationalism, is seeking to revise the European order. Now, as then, it believes that through superior cunning, and perhaps even by proving its might, it can force a larger role for itself. Now, as then, the drift toward war is gradual and easy to miss — which is exactly what makes it so dangerous. But there is one way in which today's dangers are less like those before World War I, and more similar to those of the Cold War: the apocalyptic logic of nuclear weapons. Mutual suspicion, fear of an existential threat, armies parked across borders from one another, and hair-trigger nuclear weapons all make any small skirmish a potential armageddon. In some ways, that logic has grown even more dangerous. Russia, hoping to compensate for its conventional military forces' relative weakness, has dramatically relaxed its rules for using nuclear weapons. Whereas Soviet leaders saw their nuclear weapons as pure deterrents, something that existed precisely so they would never be used, Putin's view appears to be radically different. Russia's official nuclear doctrine calls on the country to launch a battlefield nuclear strike in case of a conventional war that could pose an existential threat. These are more than just words: Moscow has repeatedly signaled its willingness and preparations to use nuclear weapons even in a more limited war. This is a terrifyingly low bar for nuclear weapons use, particularly given that any war would likely occur along Russia's borders and thus not far from Moscow. And it suggests Putin has adopted an idea that Cold War leaders considered unthinkable: that a "limited" nuclear war, of small warheads dropped on the battlefield, could be not only survivable but winnable. "It’s not just a difference in rhetoric. It’s a whole different world," Bruce G. Blair, a nuclear weapons scholar at Princeton, told the Wall Street Journal. He called Putin's decisions more dangerous than those of any Soviet leader since 1962. "There’s a low nuclear threshold now that didn’t exist during the Cold War." Nuclear theory is complex and disputable; maybe Putin is right. But many theorists would say he is wrong, that the logic of nuclear warfare means a "limited" nuclear strike is in fact likely to trigger a larger nuclear war — a doomsday scenario in which major American, Russian, and European cities would be targets for attacks many times more powerful than the bombs that leveled Hiroshima and Nagasaki. Even if a nuclear war did somehow remain limited and contained, recent studies suggest that environmental and atmospheric damage would cause a "decade of winter" and mass crop die-outs that could kill up to 1 billion people in a global famine. IV. How it would happen: The Baltics scenario In September of last year, President Obama traveled to Estonia, a nation of 1.3 million people that most Americans have never heard of, and pledged that the United States would if necessary go to war with Russia to defend it. Estonia, along with Latvia and Lithuania — together known as the Baltic states — are at the far edge of Eastern Europe, along Russia's border. They were formerly part of the Soviet Union. And they are where many Western analysts fear World War III is likeliest to start. These small countries are "the most likely front line of any future crisis," according to Stephen Saideman, an international relations professor at Carleton University. Allison and Simes, in their essay warning of war, called the Baltics "the Achilles’ heel of the NATO alliance." A full quarter of Estonia's population is ethnically Russian. Clustered on the border with Russia, this minority is served by the same Russian state media that helped stir up separatist violence among Russian speakers in eastern Ukraine. But unlike Ukraine, the Baltic states are all members of NATO, whose charter states that an attack on one member is an attack on them all. Whereas a Russian invasion of Ukraine prompted Western sanctions, a Russian invasion of Estonia would legally obligate the US and most of Europe to declare war on Moscow. "We'll be here for Estonia. We will be here for Latvia. We will be here for Lithuania. You lost your independence once before. With NATO, you will never lose it again," Obama pledged in his September speech in Estonia. Less than 48 hours after Obama's address, Russian agents blanketed an Estonia-Russia border crossing with tear gas, stormed across, and kidnapped an Estonian state security officer, Eston Kohver, who specialized in counterintelligence. Kohver has been held illegally in a Russian prison for nine months now. It was something like an act of geopolitical trolling: aggressive enough to assert Russian dominion over Estonia, but not so aggressive as to be considered a formal act of war that would trigger a Western counterattack. And it was one of several signs that Putin's Russia is asserting a right to meddle in these former Soviet territories. The Russian military has already begun pressing the Baltic states. Russian warships were spotted in Latvian waters 40 times in 2014. Russian military flights over the Baltics are now routine, often with the planes switching off their transponders, which makes them harder to spot and increases the chances of an accident. Military activity in the region had reached Cold War levels. NATO, fearing the worst, is increasing military exercises in the Baltics. The US is installing heavy equipment. And in February, the US military paraded through the Russian-majority Estonian city of Narva, a few hundred yards from Russia's borders. "Without any intention to create the big conflict, it might happen. One step, another step, and reciprocity can become very dangerous." It's a textbook example of what political scientists call the security dilemma: Each side sees its actions as defensive and the other side's as offensive. Each responds to the other's perceived provocations by escalating further, a self-reinforcing cycle that can all too easily lead to war. It is considered, for example, a major contributor to the outbreak of World War I. That it is entirely foreseeable does little to reduce the risk. Even if Russia in fact has no designs on the Baltics, its bluffing and posturing has already created the conditions for an unwanted war. In early April, for example, a Russian fighter jet crossed into the Baltic Sea and "buzzed" a US military plane, missing it by only 20 feet. It was one of several recent near-misses that, according to a think tank called the European Leadership Institute, have had a "high probability of causing casualties or a direct military confrontation between Russia and Western states." Meanwhile, Russia has been flying its nuclear-capable strategic bombers along NATO airspace, often with the planes' transponders switched off, making an accident or misperception more likely. As if that weren't dangerous enough, the bombers — hulking, decades-old Tupolev Tu-95 models — have become prone to accidents such as engine fires. What if a Tu-95 went down unexpectedly, say, off the coast of Norway? What if it was carrying nuclear warheads, or it went down during a moment of high tension? Such incidents can lead to misunderstandings, and such misunderstandings can lead to war. By late April, when NATO officials gathered at the security conference in Estonia's capital of Tallinn, the severity of the danger had become unmistakable. As Ahmed Rashid wrote from the conference: Baltic presidents and NATO officials were unusually blunt in describing the extent to which the security architecture in Eastern Europe has collapsed, how Russia poses the gravest threat to peace since World War II, and how the conflict in Ukraine and the loss of the Crimea has left the Baltic states on the front line of an increasingly hostile standoff. Amid these tensions, the thought of a plane crash leading to war seems scarily plausible. It is not just Western officials who fear such an incident could spark war. Fyodor Lukyanov, the prominent Russian analyst who is considered close to the government, worried that the NATO military exercises in the Baltics meant to deter Russia were also contributing to the problem. "Russia reacts to that because Russia perceives it as a hostile approach to the Russian border," he explained. "And it’s a vicious circle." It is easy to imagine, Lukyanov said, any number of ways that the powder keg could explode. "Without any intention to create the big conflict, it might happen," he said. "One step, another step, and reciprocity can become very dangerous. Say a Russian aircraft comes very close to an area that NATO believes is prohibited while Russia believes it’s not prohibited, and then British aircraft respond. It might be manageable, and in most cases of course it will be, but who knows." V. How it would happen: A plot to break NATO It was Andrei Piontkovsky, a Russian political analyst and frequent Kremlin critic, who first suggested the theory, last August, that Putin's plan for the Baltics was more sophisticated, and more calculated, than anybody realized. Piontkovsky was trying to answer a question that Western analysts and policymakers had been puzzling over since Russian provocations began in the Baltics last fall: What does Putin want? Unlike in Ukraine, with which Russia has a long shared history, there is little demand among the Russian public for intervention in the Baltic states. They are of modest strategic value. And the risks of Russia's aggression there are potentially catastrophic. Why bother? His is a theory that is now taken much more seriously by Western policymakers — and appears more plausible all the time. "This is his most cherished objective, to destroy NATO. The risk is big, yes? But the prize is enormous." Putin hopes to spark a conflict in the Baltics, Piontkovsky wrote, so as to force Western European leaders into an impossible choice: Fulfill their NATO obligation to defend the Baltics and counterattack, even if it means fighting World War III over a tiny post-Soviet republic most Europeans couldn't care less about — or do nothing. The implications of doing nothing, Piontkovsky pointed out, would extend far beyond the Baltics. It would lay bare NATO's mutual defense provision as a lie, effectively dissolving the military alliance, ending a quarter-century of Europe's security unification under Western leadership, and leaving Eastern Europe once more vulnerable to Russian domination. In this way, Putin could do what Soviet leaders never came close to: defeat NATO. "This is his most cherished objective," Piontkovsky told me when we talked in his kitchen, in a leafy Moscow neighborhood across the river from Gorky Park. "It's an enormous temptation. He may retreat at any stage, but the temptation is enormous, to destroy NATO. ... The risk is big, yes? But the prize is enormous." "To destroy NATO, to demonstrate that Article V does not work, the Baltic republics of Estonia and Latvia are the best place for this," he said. "It's happening now, every day. Intrusions into the airspace, psychological pressure, the propaganda on TV." He suggested that Putin, rather than rolling Russian tanks across the border, would perhaps seed unmarked Russian special forces into, say, the Russian-majority city of Narva in Estonia, where they would organize localized violence or a phony independence referendum. A handful of such unacknowledged forces, whom Putin referred to as "little green men" after they appeared in Crimea, would perhaps be dressed as local volunteers or a far-right gang; they might be joined by vigilantes, as they were in eastern Ukraine. They would almost certainly be aided by a wave of Russian propaganda, making it harder for outsiders to differentiate unmarked Russian troops from civilian volunteers, to determine who was fighting where and had started what. Such an intervention would force NATO into an impossible choice: Are you really going to open fire on some hoodlums stirring up trouble in Estonia, knowing they might actually be unmarked Russian troops? Would you risk the first major European war since 1945, all to eject some unmarked Russian troops from the Estonian town of Narva? Putin, Piontkovsky believes, is gambling that the answer is no. That NATO would not intervene, thus effectively abandoning its commitment to defend its Eastern European member states. Piontkovsky's scenario, once considered extreme, is now widely seen by Western security experts and policymakers as plausible. At the end of 2014, the military intelligence service of Denmark, a member of NATO, issued a formal paper warning of precisely that: Russia may attempt to test NATO’s cohesion by engaging in military intimidation of the Baltic countries, for instance with a threatening military build-up close to the borders of these countries and simultaneous attempts of political pressure, destabilization and possibly infiltration. Russia could launch such an intimidation campaign in connection with a serious crisis in the post-Soviet space or another international crisis in which Russia confronts the United States and NATO. "The concern is that what Putin wants to do is break NATO, and the best way to do that would be to poach on the Baltics," Saideman, the political scientist, told me on a call from a European security conference where he said the scenario was being taken very seriously. "And if Germany doesn’t respond to incursions in the Baltics, if France doesn’t respond and it’s just an American operation, then it will lead to the breaking of NATO, is the theory," he said. "That’s the biggest concern." Saideman described a variation on this scenario that I heard from others as well: that Putin might attempt to seize some small sliver of the Baltics quickly and bloodlessly. This would make it politically easier for Western European leaders to do nothing — how to rally your nation to war if hardly anyone has even been killed? — and harder to counterattack, knowing it would require a full-scale invasion. "I think they’re very serious about this," Saideman said. "There’s a real concern." VI. How it would happen: The fog of hybrid war In early 2015, Pew pollsters asked citizens of several NATO states the exact question that analysts and policymakers from Washington to Moscow are gaming out: "If Russia got into a serious military conflict with one of its neighboring countries that is our NATO ally, do you think our country should or should not use military force to defend that country?" The numbers from Western Europe were alarming: Among Germans, only 38 percent said yes; 58 percent said no. If it were up to German voters — and to at least some extent, it is — NATO would effectively surrender the Baltics to Russia in a conflict. This poll is even worse than it looks. It assumes that Russia would launch an overt military invasion of the Baltics. What would actually happen is something far murkier, and far more likely to leverage European hesitation: the playbook from Ukraine, where Russia deployed its newly developed concepts of postmodern "hybrid war," designed to blur the distinction between war and not-war, to make it as difficult as possible to differentiate grassroots unrest or vigilante cyberattacks from Russian military aggression. Putin may already be laying the groundwork. In March of 2014, shortly after Russia had annexed Crimea, Putin gave a speech there pledging to protect Russians even outside of Russia, which many took as a gesture to the substantial Russian minorities in the Baltics. "That kind of misperception situation is definitely possible, and that’s how wars start" Then, in October, Putin warned that "open manifestations of neo-Nazism" had "become commonplace in Latvia and other Baltic states" — repeating the language that he and Russian state media had earlier used to frighten Russian speakers in Ukraine into taking up arms. This April, several Russian outlets issued spurious reports that Latvia was planning to forcibly relocate ethnic Russians into Nazi-style ghettos — an echo of similar scaremongering Russian propaganda broadcast in the runup in Ukraine. Martin Hurt, a former senior official of the country's defense ministry, warned that his country's ethnic Russian minority could be "receptive to Kremlin disinformation." Moscow, he said, could generate unrest "as a pretext to use military force against the Baltic states." In early 2007, Estonia's parliament voted to relocate a Soviet-era military statue, the Bronze Soldier, that had become a cultural symbol and annual rallying point for the country's ethnic Russians. In response, Russian politicians and state media accused the Estonian government of fascism and Nazi-style discrimination against ethnic Russians; they issued false reports claiming ethnic Russians were being tortured and murdered. Protests broke out and escalated into riots and mass looting. One person was killed in the violence, and the next day hackers took many of the country's major institutions offline. Russia could do it again, only this time gradually escalating further toward a Ukraine-style conflict. NATO is just not built to deal with such a crisis. Its mutual defense pledge, after all, rests on the assumption that war is a black-and-white concept, that a country is either at war or not at war. Its charter is from a time when war was very different than it is today, with its many shades of gray. Russia can exploit this flaw by introducing low-level violence that more hawkish NATO members would consider grounds for war but that war-averse Western European states might not see that way. Disagreement among NATO's member states would be guaranteed as they hesitated over where to declare a moment when Russia had crossed the line into war. Meanwhile, Russian state media, which has shown real influence in Western Europe, would unleash a flurry of propaganda to confuse the issue, make it harder to pin blame on Moscow for the violence, and gin up skepticism of any American calls for war. Germany, which is widely considered the deciding vote on whether Europe would go to war, would be particularly resistant to going to war. The legacy of World War II and the ideology of pacifism and compromise make even the idea of declaring war on Russia unthinkable. German leaders would come under intense political pressure to, if not reject the call to arms, then at least delay and negotiate — a de facto rejection of NATO's collective self-defense. In such a scenario, it is disturbingly easy to imagine how NATO's European member states could split over whether Russia had even crossed their red line for war, much less whether to respond. Under a fog of confusion and doubt, Russia could gradually escalate until a Ukraine-style conflict in the Baltics was foregone, until it had marched far across NATO's red line, exposing that red line as meaningless. But the greatest danger of all is if Putin's plan were to stumble: By overreaching, by underestimating Western resolve to defend the Baltics, or by starting something that escalates beyond his control, it could all too easily lead to full-blown war. "That kind of misperception situation is definitely possible, and that’s how wars start," Saideman said, going on to compare Europe today with 1914, just before World War I. "The thing that makes war most thinkable is when other people don’t think it’s thinkable." In 1963, a few months after the Cuban missile crisis had almost brought the US and Soviet Union to blows, President John F. Kennedy gave a speech drawing on the lessons of the world's brush with nuclear war: "Above all, while defending our vital interests, nuclear powers must avert those confrontations which bring an adversary to a choice of either a humiliating retreat or a nuclear war." That is the choice that Putin may well force upon NATO. VII. How it would happen: The Ukraine scenario Evgeny Buzhinsky has spent much of his professional life with the threat of global nuclear destruction hanging over his head. A lifelong Russian military officer, he earned his PhD in military sciences in 1982, just as the Cold War entered one of its most dangerous periods, and rose to the General Staff, where he remained for years after the Soviet Union's collapse, through periods of calm and of tension. He retired in 2009 as a lieutenant general and remains active in Russian national security circles, now heading the PIR Center, a well-respected Russian think tank that focuses on military, national security, and arms control issues. Buzhinsky, when I met him in Moscow, had a warning for me. Those in the West who worried about the possibility of a major war breaking out in the Baltics were missing the real threat: Ukraine. The US, he feared, does not appreciate how far Russia is willing to go to avoid a defeat in Ukraine, and this miscalculation could pull them into conflict. Read the full interview with former Russian General Evgeny Buzhinsky "Ukraine, for Russia, is a red line," he warned. "And especially a Ukraine that is hostile to Russia is a definite red line. But the US administration decided that it's not." This was a concern I heard more than once in Russia. When Fyodor Lukyanov, the Moscow foreign policy insider, warned that Russian foreign policy officials saw a major war as increasingly possible, and I asked him how they thought it would happen, he cited Ukraine. "For example, massive military help to Ukraine from the United States — it could start as a proxy war, and then ..." he trailed off Lukyanov worried that the US does not understand Russia's sense of ownership over Ukraine, the lengths it would go to protect its interests there. "It’s seen by many people as something that’s actually a part of our country, or if not part of our country then a country that’s absolutely essential to Russia’s security," he said. Buzhinsky is one of those people. Like Lukyanov and other Russian analysts, he worried that the United States had wrongly concluded that Putin would ultimately acquiesce if he faced likely defeat in Ukraine. The Americans, he said, were dangerously mistaken. Gregarious, bear-sized, and clearly accustomed to dealing with Westerners from overseeing arms control treaties during much of the 1990s, Buzhinsky sipped a grapefruit juice when we met in downtown Moscow. "A year ago, I was absolutely convinced Russia would never intervene militarily," he said about the possibility of a full, overt Russian invasion of Ukraine. "Now I'm not so sure." The view of the Russian government, he said, was that it could never allow the defeat of the pro-Russia separatist rebels in the eastern Ukraine region sometimes called Donbas. (In August, when those rebels appeared on the verge of defeat, Russia provided them with artillery support and covertly sent troops to fight alongside them, none of which Moscow has acknowledged.) If Ukrainian forces were about to overrun the separatist rebels, Buzhinsky said, he believed that Russia would respond not just with an overt invasion, but by marching to Ukraine's capital of Kiev. "A massive offensive on the Ukrainian side" against the rebels, he said, would lead Russia to openly enter the war. "A war with Russia in Ukraine — if Russia starts a war, it never stops until it takes the capital." When I asked Buzhinsky if he really believed Putin would launch a full Russian invasion of Kiev in response to a Ukrainian effort to retake Donbas, he answered, "Yes, definitely. He said twice publicly, 'I won't let it happen.' As he is a man of his word, I am sure he will." Such a scenario, he said, could lead to a larger conflict no one wants. The Americans believe that "Russia will never dare, Putin will never dare, to interfere," leaving the US unprepared in case it should happen. "And then I could not predict the reaction of the United States and NATO." Buzhinsky outlined another way he feared Ukraine could lead to a larger war. If the US provided sophisticated military equipment to Ukraine that required putting American trainers or operators near the front lines, and one of them was killed, he believed the US might feel compelled to intervene outright in Ukraine. Would Russia really risk a major war over Ukraine, one of Europe's poorest countries? For months, Moscow has been suggesting that Western military involvement in Ukraine, even something as mild as providing the Ukrainian military with certain arms, would be taken as an act of war against Russia. Like Putin's threats to use nuclear weapons, this has been shrugged off as bluster, mere rhetoric, just for scoring domestic political points. What Buzhinsky was trying to underline to me was that the threats are real — that Russia might consider its interests in Ukraine so vital that it would risk or even fight a war to protect them. He was not alone in saying this — I heard it from many others in Moscow, including Russian analysts who are critical of their country's Ukraine policy as too aggressive. Buzhinsky explained that Russia had set this as a red line out of the fear that a Ukrainian reconquest of eastern Ukraine would lead to "the physical extermination of the people of Donbas," many of whom are Russian speakers with cultural links to Russia. Russian state media has drilled this fear into the peoples of Ukraine and Russia for a year now. It does not have to be true to serve as casus belli; Moscow deployed a similar justification for its annexation of Crimea. "You don't get to walk this back" The connection to Ukraine is often expressed by everyday Russians as an issue of cultural heritage; Kievan Rus, a medieval Slavic federation with its capital in the present-day Ukrainian capital of Kiev, is something like Russia's predecessor state. But this is likely about more than nationalism or kinship with Russian-speaking Ukrainians. Moscow is notorious for its conviction that the US is bent on Russia's destruction, or at least its subjugation. It is paranoid and painfully aware of its isolation and its comparative weakness. A hostile and pro-Western Ukraine, Putin may have concluded, would pose an existential threat by further weakening Russia beyond what it can afford. Allison and Simes, in their essay on the risk of war, described Ukraine as a potential ground zero for wider conflict because of this. "Russia’s establishment sentiment holds that the country can never be secure if Ukraine joins NATO or becomes a part of a hostile Euro-Atlantic community," they wrote. "From [Moscow's] perspective, this makes Ukraine’s non-adversarial status a non-negotiable demand for any Russia powerful enough to defend its national-security interests." It is practically a cliché in international relations: "Russia without Ukraine is a country, Russia with Ukraine is an empire." Putin's Russia appears to believe that reclaiming great-power status is the only way it can guarantee security against a hostile West. Jeffrey Lewis, an arms control expert, traced this Russian government obsession with Ukraine back to Putin's political weakness at home, as well as Russia's sense of military insecurity against a hostile and overwhelmingly powerful West. "I suspect that the desire to unite the Russian world and to subjugate the non-Russian neighbors is driven by a fundamental sense of insecurity," Lewis said in a much-circulated September podcast on Putin's nuclear threats. "That, like the Soviet leadership, he has to try very hard to stay in power, and so there’s a tendency as his legitimacy declines to try to blame outside forces. And the problem is that when you try to look at the world in that conspiratorial way, there’s always a justification for subjugating the next set of neighbors." This means that should the US or other Western countries become sufficiently involved in Ukraine that Russia cannot maintain control of the conflict, then Russia may feel this puts it at such existential threat that it has no choice but to escalate in response. Even at the risk of war. Russia knows it would lose a full-blown war with NATO, of course, but it has other options. An official with the Russian Defense Ministry's public advisory board told the Moscow Times that should Western countries arm Ukraine's military, it would respond by escalating in Ukraine itself as well as "asymmetrically against Washington or its allies on other fronts." Russian asymmetrical acts — cyberattacks, propaganda operations meant to create panic, military flights, even little green men — are all effective precisely because they introduce uncertainty and risk. If that sounds dangerous, it is. American and NATO red lines for what acts of "asymmetry" would and would not trigger war are unclear and poorly defined. Russia could easily cross such a line without meaning to, or could create enough confusion that the US believes it or its allies are under a severe enough threat to demand retaliation. "You don't get to walk this back," Matthew Rojansky, the director of the Kennan Institute, warned in comments to the New York Times about what could happen if the US armed Ukraine's military, as Congress is pushing Obama to do. "Once we have done this we become a belligerent party in a proxy war with Russia, the only country on Earth that can destroy the United States," Rojansky said. "That’s why this is a big deal."

VIII. The nuclear dangers: The red line is closer than you think This August, as the Russian military launched its undeclared and unofficial invasion of eastern Ukraine to defend separatist rebels there against defeat, Putin attended an annual youth conference at Lake Seliger, just north of Moscow. During a Q&A session, a teaching student asked an odd question about the "cyclical" nature of history and concerns that Russia could be "drawn into a new, open global conflict." Putin, in his answer, did something that the leaders of major nuclear powers generally avoid doing — he rattled the nuclear saber a bit: Let me remind you that Russia is one of the world’s biggest nuclear powers. These are not just words — this is the reality. What’s more, we are strengthening our nuclear deterrent capability and developing our armed forces. They have become more compact and effective and are becoming more modern in terms of the weapons at their disposal. There is a certain fear in Russia, never far from the surface, that the only thing preventing the West from realizing its dream of destroying or subjugating Russia is its nuclear arsenal. (Three months later, Putin warned that the West wanted to tame the Russian bear so as to "tear out his fangs and his claws," which he explained meant its nuclear weapons.) "There is a widespread belief that the only guarantee for Russian security, if not sovereignty and existence, is the nuclear deterrent," Lukyanov, the Russian foreign policy expert, explained. "After the Yugoslavia wars, Iraq War, Libyan intervention, it’s not an argument anymore, it’s conventional wisdom: 'If Russia were not a nuclear superpower, the regime change of an Iraqi or Libyan style would be inevitable here. The Americans are so unhappy with the Russian regime, they would do it. Praise God, we have a nuclear arsenal, and that makes us untouchable.'" But Russia faced a problem: Its conventional military forces are now so much weaker than NATO's, and its capital city so close to NATO's forces in the Baltics, that it feared NATO tank divisions could push all the way to Moscow and quickly win a war without ever using a nuclear weapon. Both the US and Russia had pledged to use nuclear weapons only to deter one another from nuclear attacks. This kept the Cold War cold. But because the US would not need its ICBMs to win a war, that deterrence is no longer enough to keep Russia safe. In response, Russia has been gradually lowering its bar for when it would use nuclear weapons, and in the process upending the decades-old logic of mutually assured destruction, adding tremendous nuclear danger to any conflict in Europe. The possibility that a limited or unintended skirmish could spiral into nuclear war is higher than ever. Russia's nuclear doctrine, a formal document the Kremlin publishes every few years outlining when it will and will not use nuclear weapons, declares that the Russian military can launch nuclear weapons not just in the case of a nuclear attack, but in case of a conventional military attack that poses an existential threat. In other words, if Russia believes that American tanks could be bound for the Kremlin, it has declared it may respond by dropping nuclear bombs. The danger that this adds to any possible confrontation, particularly along the Baltic states, is difficult to overstate. If an accident or miscalculation were to lead to a border skirmish, all it would take is for the Kremlin to misperceive the fighting as the beginning of an assault toward Moscow and its own doctrine would call for using nuclear weapons. Indeed, it would be the only way to avoid total defeat. There is another layer of danger and uncertainty to this: It is not clear what Russia would consider a conventional threat worthy of a nuclear response. A few months after he'd annexed Crimea, Putin revealed that during Russia's undeclared invasion of the territory he had considered putting his country's nuclear forces on alert; his government has signaled it would consider using nuclear force to defend Crimea from an attack, something Russian analysts told me was not just bluster. The United States, of course, has no intention of militarily retaking Crimea, despite surprisingly common fears to the contrary in Russia. But Russian paranoia about such a threat, and a possible willingness to use nuclear weapons to avert it, adds more danger to the already dangerous war in eastern Ukraine and the fears that greater Russian or Western involvement there could spark a broader conflict. And the Crimea revelation raises a disconcerting question: Where exactly does Moscow place the line for a threat severe enough to use nuclear weapons? Its doctrine says they should be used only against an existential threat, but an attack on Crimea would be far from existentially dangerous. We can only guess where the real red line lays, and hope not to cross it by mistake. IX. The nuclear dangers: How Putin is pushing us back to the brink There is a specific moment that arms control experts often cite to highlight the dangers of nuclear weapons, how they kept the world poised, for years at a time, mere minutes away from nuclear devastation. That moment was September 26, 1983. That evening, a Russian lieutenant colonel named Stanislav Petrov settled in for his shift overseeing the Soviet Union's missile attack early warning system. Petrov had a top-secret network of satellites, all pointed squarely at the United States and its arsenal of nuclear-armed intercontinental ballistic missiles, which pointed back at him. The US and Soviet Union were ramping up development of ICBMs, which could circle the globe in 30 minutes and reduce an enemy city to ash. Both sides were driven by fear that the other could one day gain the ability to launch a preemptive nuclear strike so devastating and so fast that it would start and win the war within hours. Each sought to develop ever more sensitive warning systems, and ever more rapid mechanisms for retaliation, to deter the threat. Petrov ran one such warning system. If he caught an American attack as soon as it crossed his sensors, it would give the Soviet leadership about 20 minutes of warning time. That was their window to determine how to respond. The space for mistakes was effectively zero. Five hours into Petrov's shift that night, something he had never encountered in his 11-year career happened: The system went into full alarm. The word "LAUNCH" displayed in large red letters. The screen announced a "high reliability" of an American ICBM barreling toward the Soviet Union. Petrov had to make a decision: Would he report an incoming American strike? If he did, Soviet nuclear doctrine called for a full nuclear retaliation; there would be no time to double-check the warning system, much less seek negotiations with the US. If he didn't, and he was wrong, he would have left his country defenseless, an act tantamount to treason. His gut instinct told him the warning was in error, but when he flipped through the incoming imagery and data and he could reach no hard conclusion from it. After a few moments, he called his superiors and stated categorically that it was a false alarm. There was, he insisted, no attack. Petrov waited in agony for 23 minutes — the missile's estimated time to target — before he knew for sure that he'd been right. Only a few people were aware of it at the time, but thanks to Petrov, the world had only barely avoided World War III and, potentially, total nuclear annihilation. The US and Soviet Union, shaken by this and other near-misses, spent the next few years stepping back from the brink. They decommissioned a large number of nuclear warheads and signed treaties to limit their deployment. One of their most important measures was a 1987 agreement called the Intermediate-Range Nuclear Forces (INF) Treaty, which saw both sides conclude that the medium-range, land-based nuclear missiles they'd stuffed across Europe were simply too dangerous and destabilizing to be allowed. Because the missiles could reach Moscow or Berlin or London at lightening speeds, they shortened the "response time" to any crisis — the window in which a Soviet or Western leader would have to decide whether the country was under attack before such an attack would hit — to just a few minutes. They made the danger of an unintended escalation, or of an error like the that one Petrov only barely prevented, far greater. The risk they posed was deemed, in the 1987 INF Treaty, unacceptable to the world. And the weapons were removed. Putin has taken several steps to push Europe back toward the nuclear brink, to the logic of nuclear escalation and hair-trigger weapons that made the early 1980s, by many accounts, the most dangerous time in human history. Perhaps most drastically, he appears to have undone the 1987 INF Treaty, reintroducing the long-banned nuclear weapons. In March, Russia announced it would place nuclear-capable bombers and medium-range, nuclear-capable Iskander missiles in the Russian enclave of Kaliningrad — only an hour, by commercial airliner, from Berlin. Meanwhile, it has been testing medium-range, land-based missiles. The missiles, to the alarm of the United States, appear to violate the INF Treaty. This is far from Putin's only nuclear escalation. He is developing more nuclear weapons, and calling frequent attention to them, as apparent cover for his aggression and adventurism in Europe. There are suspicions, for example, that Russia may have deployed nuclear-armed submarines off of the US Eastern Seaboard. What makes this so dangerous is that Putin appears to believe, as the scholar Edward Lucas outlined in a recent report for the Center for European Policy Analysis, that he has a greater willingness than NATO to use nuclear weapons, and thus that his superior will allows him to bully the otherwise stronger Western powers with games of nuclear chicken. This is a substantial, and indeed terrifying, break from Cold War–era nuclear thinking, in which both sides rightly feared nuclear brinksmanship as too dangerous to contemplate and used their weapons primarily to deter one another. "Russia’s nuclear saber-rattling is unjustified, destabilizing and dangerous," NATO Secretary-General Jens Stoltenberg said in a May speech in Washington. Putin is acting out of an apparent belief that increasing the nuclear threat to Europe, and as a result to his own country, is ultimately good for Russia and worth the risks. It is a gamble with the lives of hundreds of millions of Europeans, and perhaps many beyond, at stake. X. The nuclear dangers: An atomic gun to the world's head The view among many Western analysts is that the nuclear-capable missiles are meant as a gun against the heads of the Americans and the Europeans: You better not mess with us Russians, or who knows what we'll do. Putin himself endorsed this view in a 2014 speech in Sochi, where he approvingly cited Soviet leader Nikita Khrushchev's 1960 address to the United Nations, when he hammered his shoe on the podium. "The United States and NATO thought, 'This Nikita is best left alone, he might just go and fire a missile. We better show some respect for them,'" Putin said. This sort of a nuclear threat could be a perfect way for Putin to attempt the sort of NATO-splitting scenario described by analysts like Piontkovsky. What if, Lucas asked as an example in his report, Putin found some excuse to declare a Russian "military exclusion zone" in the Baltic Sea, thus physically cutting off the Baltic states from the rest of NATO? "Would America really risk a nuclear standoff with Russia over a gas pipeline?" Lucas asked. "If it would not, NATO is over. The nuclear bluff that sustained the Western alliance through all the decades of the Cold War would have been called at last." Putin's love of brinksmanship, while perhaps born of Russia's weakness, is also deeply worrying for what it says about the leader's willingness and even eagerness to take on huge geopolitical risk. "Either he has a very weird theory of nuclear weapons, or he just doesn’t take the West seriously and is trying to cow us with whatever threat he can make," Saideman, the political scientist, said, going on to draw yet another of the many parallels analysts have drawn to the onset of World War I. "There are two visions of international relations: One is that threats work, and one is that threats don’t, where they cause counter-balancing," Saideman continued. "This was the theory of the [German] Kaiser before World War I: the more threatening you are, the more people will submit to your will. That might be Putin’s logic, that he’s just going to threaten and threaten and hope that NATO bends. But the long run of international relations suggests that it goes the other way, where the more threatening you are the more you produce balancing." In other words, Putin is hoping to compensate for his weakness by expressing his willingness to go further, and to raise the stakes higher, than the more powerful Western nations. But his actions are premised on a flawed understanding of how the world works. In fact, he is virtually forcing the West to respond in kind, raising not just the risk of a possible war, but the ease with which such a war would go nuclear. XI. The nuclear dangers: Does Putin believe nuclear war can be "won"? There is a corollary in Russia's nuclear doctrine, a way in which the Russians believe they have solved the problem of Western military superiority, that is so foolhardy, so dangerous, that it is difficult to believe they really mean it. And yet, there is every indication that they do. That corollary is Russia's embrace of what it calls a "de-escalation" nuclear strike. Go back to the scenario spelled out in Russia's military doctrine: a conventional military conflict that poses an existential threat to the country. The doctrine calls for Russia to respond with a nuclear strike. But imagine you're a Russian leader: How do you drop a nuclear bomb on NATO's troops without forcing the US to respond with a nuclear strike in kind, setting off a tit-for-tat cycle of escalation that would end in total nuclear war and global devastation? Russia's answer, in the case of such a conflict, is to drop a single nuclear weapon — one from the family of smaller, battlefield-use nukes known as "tactical" weapons, rather than from the larger, city-destroying "strategic" nuclear weapons. The idea is that such a strike would signal Russia's willingness to use nuclear weapons, and would force the enemy to immediately end the fight rather than risk further nuclear destruction. Nikolai Sokov, a nuclear weapons expert and former official in the Russian Foreign Affairs Ministry, explained in the Bulletin of Atomic Scientists that this is not a far-fetched option of last resort; it has become central to Russian war planning. "Such a threat is envisioned as deterring the United States and its allies from involvement in conflicts in which Russia has an important stake, and in this sense is essentially defensive," Sokov wrote. "Yet, to be effective, such a threat also must be credible. To that end, all large-scale military exercises that Russia conducted beginning in 2000 featured simulations of limited nuclear strikes." Buzhinsky, the recently retired member of Russia's General Staff, confirmed in our meeting that this is something the military sees as a viable option. "If Russia is heavily attacked conventionally, yes, of course, as it's written in the doctrine, there may be limited use of nonstrategic nuclear weapons," he said. "To show intention, as a de-escalating factor." It is difficult to imagine a more dangerous idea in the world of military planning today than of a "limited" nuclear war. Scholars have debated for decades, and still debate today, whether the concept of limited nuclear war is realistic, or whether such a conflict would inevitably spiral into total nuclear war. Put another way, no one knows for sure whether Russia's military planners have sown the seeds for global nuclear destruction. Seen from the Russian side, it is at least possible to imagine how this doctrine might make sense: The threat of NATO's conventional forces is widely seen as both overwhelming and imminent, making such an extreme step worth considering. Ever since the fall of the Soviet Union, Russia's strategic culture has increasingly emphasized its nuclear arsenal, the one remaining legacy of its fearsome great-power status. It is a sort of Russian cult of the nuclear weapon, or even a certain strategic fetish. With nukes so central to Russian strategic thinking, it is little wonder Moscow sees them as the solution to its greatest strategic problem. But when you consider this doctrine from the American side, you begin to see what makes it dangerous, even insane. Imagine that you are an American leader and your forces in Eastern Europe have somehow been drawn into conflict with the Russians. Perhaps, as artillery and planes from within Russia hammer your forces, you counterattack on Russian soil to take them out. The Kremlin, fearing the start of an invasion to take Moscow, drops a tactical nuclear warhead on your forces in Estonia or Latvia. You have no idea whether more Russian nuclear strikes are coming, either on the battlefield, more widely on Europe, or even against Washington or New York. Do you respond with an in-kind tactical nuclear strike, opening the risk of gradual escalation to total nuclear war? Do you, fearing the worst, move to take out the Russian leadership before they can order more attacks? Or do you announce a unilateral ceasefire, drawing your forces back in humiliation, rewarding Russia with a victory? It is difficult to imagine a more dangerous idea than "limited" nuclear war Russia's nuclear doctrine is betting that any American leader — not to mention the leaders of nuclear-armed France and the UK — would choose the last of those three options. If that prediction turned out to be wrong, it would mean nuclear war, perhaps global nuclear war and thus annihilation. This doctrine, in other words, is gambling with the fate of the world. Such a scenario, to be clear, is remote, as are all of the nuclear scenarios. It would require a cascading series of events, and for neither side to pull back in time as those events built. The odds of this happening are quite low. But they are greater than zero, and growing. Such a scenario is within the realm of possibility — if it were not, then Russia would not regularly conduct military exercises that imagine exactly this outcome. And recall that Alexander Vershbow, the deputy secretary general of NATO, told a conference in late April that NATO is gaming out exactly such a crisis. There are yet more worrying implications to this Russian doctrine. Its logical conclusion is that Russia sees itself as able to fight a war with the conventionally superior United States without losing, and that it can do this by using battlefield nuclear weapons. Under this doctrine, Moscow is deeming not only full-blown war against the US as imaginable, but a full-blown war with at least one nuclear detonation. That, perhaps, can help explain why Putin has seemed so willing to ratchet up the possibility of a real war with the United States, even one involving nuclear threats — he may believe that through his superior will and brinksmanship, he can avoid defeat. Adding a nuclear element to any conflict would also seem to increase the odds of NATO's Western European members splitting over how to respond, particularly if Russian propaganda can make the circumstances leading up to the detonation unclear. But this also shows the degree to which his entire strategy may rest in part on a shoddy premise — that "limited" nuclear war can be winnable — and one that puts the entire world at risk. XII. The nuclear dangers: End games President Dwight Eisenhower held office at a time when the prospect of a nuclear war was relatively new and military planners unsure how to account for the possibility of a conflict with the Soviet Union in which both sides might use nuclear weapons. Though some in his administration urged him to consider plans for nuclear conflict, Eisenhower, no stranger to war, rejected the idea as unthinkable. "You just can't have this kind of war," Eisenhower said in 1957. "There aren't enough bulldozers to scrape the bodies off the streets." Putin believes he has found a way around this problem, relying on smaller, battlefield-use warheads that could win a war without escalating to a global conflict in which whole cities were sacrificed. But even a limited nuclear war could be catastrophic, and not just for the nations where the bombs would fall, but for the whole world. A 2008 study (updated in 2014) on the environmental effects of a "small" nuclear war described what would happen if 100 Hiroshima-strength bombs were detonated in a hypothetical conflict between India and Pakistan. This is equivalent to less than 1 percent of the combined nuclear arsenals of the US and Russia. The explosions, the study found, would push a layer of hot, black smoke into the atmosphere, where it would envelop the Earth in about 10 days. The study predicted that this smoke would block sunlight, heat the atmosphere, and erode the ozone for many years, producing what the researchers call without hyperbole "a decade without summer." As rains dried and crops failed worldwide, the resulting global famine would kill 1 billion people. "We escaped the Cold War without a nuclear holocaust by some combination of skill, luck and divine intervention, and I suspect the latter in greatest proportion," General George Lee Butler of the US Strategic Air Command told the journalist Eric Schlosser for his book on the dangers of nuclear weapons. We may have escaped the Cold War, but we have not escaped the nuclear threat, which not only remains but is growing. The sense that this danger is resigned to history books, common in Washington and other Western capitals, is precisely part of its danger. It is another echo of the months and years before World War I, when the world drifted unknowingly toward disaster. In April of last year, just after Russia had annexed Crimea, the London-based think tank Chatham House published a report on the dangers of unintended nuclear conflict. It was not pegged to the events in Ukraine, and at that point few people, including the report's authors, saw Crimea as the potential beginning of a larger conflict. Even still, it was dire in its warnings. "The probability of inadvertent nuclear use is not zero and is higher than had been widely considered," it stated. "The risk associated with nuclear weapons is high" and "under-appreciated." Their warnings were widely ignored. As the report itself noted, the world has concluded, wrongly, that nuclear weapons no longer pose an imminent threat. Attention has moved on. But the seeds of a possible war are being sown in Europe. Should the worst happen, which is a remote but real possibility, the consequences will follow all Americans to their homes. Amanda Taub Editor: Ezra Klein Data Visualization: Javier Zarracina Lede Image Design: Anand Katakam Body Image Design: Aidan Feay Producer: Chao Li