Nearly two years ago, following the Russian seizure of Crimea, I explained that the West was in a new Cold War with the Kremlin—whether we like it or not. The aggressive moves of President Vladimir Putin, particularly in Ukraine, in the early spring of 2014 created a situation of hostility short of all-out conflict, rather a semi-war, something I’ve termed Special War. The good news for us is that Russia, an intrinsically weak state, is eminently able to be deterred by a far stronger NATO.

However, that analysis was rejected by the White House, as well as most Western foreign policy mavens, as alarmist, and none of my recommendations on how to prevent Cold War 2.0 from going hot were implemented by the Obama administration. As a result, Russia has been anything but deterred, as its military intervention in Syria’s terrible civil war last year demonstrated, to say nothing of Mr. Putin’s saber-rattling in Eastern Europe.

Yet my view is now officially the Kremlin’s too (it’s been Moscow’s unofficial take far longer) as evidenced by a series of alarming statements by top Russian officials in recent days. Over the weekend, Prime Minister Dmitri Medvedev explained, “We have slid back to a new Cold War”—of course he blamed the West for this—to the shock of attendees at Munich’s annual security conference, Europe’s premier event of this kind. Mr. Medvedev has long been viewed by optimistic Westerners as the Kremlin’s gentler “good cop” compared to President Putin’s rougher-hewn KGB ways, but that illusion, like so many others, has now evaporated.

Last week I explained in this column how Mr. Putin’s aggressive moves in Syria, combined with rash Turkish reactions and President Obama’s many missteps, have created a truly dangerous situation where a third World War is now all too possible. As if on cue, the next day Sergei Lavrov, Russia’s foreign minister, stated that “a new world war” indeed was now possible over Syria. It’s not every day that the top diplomat of a nuclear power talks openly about world war.

Prime Minister Medvedev then echoed Mr. Lavrov’s alarming statement by warning of “a new world war” in an interview with a German newspaper. The Kremlin promptly objected and released a Russian-language version of the interview that included the gentler phrase “another war on earth.” This appears to be a trademark Moscow provocation since the German-language interview unmistakably says “a new world war” (einen neuen Weltkrieg). Releasing different translations of key statements is an old KGB trick that Mr. Putin’s regime has played on the West more than once, but here they are truly playing with fire.

Mr. Putin has played his militarily weak hand well so far, and doubling-down on aggression has paid handsome dividends for him too.

Of course, Mr. Putin and other top Kremlin officials have been breathing fire against the West for years, and only now are mainstream figures in Western foreign policy circles taking much public notice. At the Munich security conference way back in 2007, Mr. Putin delivered an angry speech blaming the United States for global instability and lashed out at NATO too. Noteworthy was this critique of American policy: “They bring us to the abyss of one conflict after another…Political solutions are becoming impossible.”

Although the grave implications of Mr. Putin’s speech were clear to anyone wanting to see, particularly when combined with major reforms and reinvestment in the Russian military that started at roughly the same time, most Western “experts” did not wake up, and it took the Russian interventions in Georgia in 2008, Ukraine in 2014, and now Syria to shake our foreign policy elites out of their torpor. When one side says we’re in a new Cold War, we are—“the enemy gets a vote” is one of the most important, as well as most neglected, of strategic aphorisms—no matter how much Mr. Obama and others in the West seek to deny it.

What, then, is to be done? Avoiding all-out war with Moscow is the clear goal before us, just as it was throughout the last Cold War, and achieving that is not particularly difficult if NATO develops the will to do so. As yet, however, that will—as expressed in major increases in defense spending and a degree of seriousness about conventional deterrence—is lacking, and our president shows no signs of changing his tune on this. To be fair, neither do many European leaders.

Thus Mr. Putin has a window of opportunity between now and mid-January 2017, when the next American president enters the White House, to achieve his strategic aims in Eastern Europe. Doing that means breaking NATO by showing the Atlantic Alliance to be hollow, an unimportant relic from the last Cold War. The risk of the Kremlin rolling the dice against NATO sometime this year is real. Mr. Putin has played his militarily weak hand well so far, and doubling-down on aggression has paid handsome dividends for him too. Not to mention that the very real contraction of the Russian economy, between Western sanctions and the collapse of global oil markets, may not encourage moderation in Moscow, rather the opposite.

In military terms, any protracted war between NATO and Russia, assuming it does not result in nuclear Armageddon, will end badly for the Kremlin. Yet early successes by the Russians are likely, as explained in a new study by the RAND Corporation, based on recent war games, demonstrating that the Baltic States would be quickly overrun by Russian forces in the event of war, long before significant American power could be brought to bear.

Although Warsaw punches above its weight in NATO, its efforts to get the Obama administration to take Polish warnings about Russia seriously have made little headway.

This is well known inside NATO but not something the public hears about much. It’s precisely why I have advocated a serious deterrence force being stationed in Eastern Europe since mid-2014, and yet the Obama administration has done almost nothing to achieve this. At present U.S. Army Europe has many chiefs yet few Indians. Its combat forces are an infantry brigade in Germany and an airborne brigade in Italy, less than 10,000 boots on the ground, all far from the potential battlefields to the East. The latter in particular would be little more than a speed bump to Russian armored forces.

With fanfare at the beginning of this month, the White House announced the grandly titled European Reassurance Initiative with an encouraging press release boasting that Pentagon spending on Europe was being quadrupled next year, the lion’s share of that going to the U.S. Army to improve conventional deterrence against Russia.

Like so many defense initiatives by this White House, however, there’s less here than meets the eye. Two heavy (i.e. armored) brigades were taken away from U.S. Army Europe earlier in Mr. Obama’s tenure, and the ERI is bringing them back—sort of. They will be back on the books but reconstituted with personnel being rotated, not permanently based, in Europe. Plus there’s a real question whether the army, which is short of troops and units and has many more global obligations that it can presently meet, can really achieve this.

Not to mention that these brigades will be based in Central Europe, probably in Germany, hundreds of miles from NATO’s eastern frontier, where they are needed to deter Russian aggression. If the Atlantic Alliance wants to prevent Russian military moves—a quick land grab on Estonia is a commonly cited scenario—then armored forces must be able to reach the battlefield quickly, not the several days it would take them to get to the Baltics from Central Europe. They would arrive after the Baltics were already under Russian control.

Poland is the key to deterring the Russians in Europe. Warsaw takes defense seriously, its military budget having been significantly increased to meet the new threat from the East. Poland has been pleading for American troops in their country to no avail. Although Warsaw punches above its weight in NATO, its efforts to get the Obama administration to take Polish warnings about Russia seriously have made little headway.

Warsaw was raising the alarm about Mr. Putin’s designs on Eastern Europe years ago (they understood the implications of his 2007 Munich speech) and began revamping their military to deter the Russians six months before the invasion of Crimea, but it’s proven impossible to get the attention of this White House. Mr. Obama has a track record of needlessly offending the Poles, our only militarily significant “new NATO” ally, and things have not improved much of late.

‘The White House doesn’t listen to us, even on detailed military matters—it’s the usual Obama game: Let’s have lots of long meetings, and then the NSC will make all the decisions anyway.’

Even the much-touted ERI is disappointment to the Poles, who expected that at least some of the American military units returning to Europe would be based in their country. But none will be, notwithstanding the fact that basing units in Poland would be far cheaper than moving them to Germany, or anywhere in “old NATO.” Polish efforts to get the Pentagon to even discuss basing U.S. Army units in Poland got nowhere in recent high-level talks between Washington and Warsaw. “They’re still not serious about deterring the Russians,” a senior Polish defense official said after these discussions. “Maybe the next White House will be; we can only hope.”

Although some senior American defense officials are sympathetic to the Poles and agree that putting U.S. Army units in Central Europe, hundreds of miles from where they need to be to deter Russian aggression, makes no strategic sense, they feel powerless. “The White House doesn’t listen to us, even on detailed military matters,” one senior officer said at the Pentagon. “It’s the usual Obama game: Let’s have lots of long meetings and then the NSC will make all the decisions anyway,” citing the commonly held view in defense circles of how the National Security Council works in this White House.

The Russians are turning up the heat on Europe right now. Their espionage against the West is at the highest levels seen in decades, in some countries higher than it was even during the Cold War. Norwegian intelligence has just explained that Russian espionage, both cyber and old fashioned, is a major threat to the country and its stability. German officials recently admitted that aggressive cyberespionage against Berlin, including hacking the country’s parliament, was “clearly” the work of Russian intelligence.

In addition, a Kremlin hand is detectable in the mass migrant flows that are roiling the European Union. Finland, a country of five million that is facing as many as one million migrants coming from the East, recently warned NATO that the Russians are assisting migrant flows, considered by many Europeans to be tantamount to invasion. Moreover, the Kremlin seems perfectly happy to let Syria’s fratricide continue with millions more refugees headed to Europe.

As if the resulting destabilization of Europe were not enough, Moscow manipulates European media, pushing lurid tales of migrant crimes that are changing politics rapidly. Kremlin outlets recently went wild with a story about a 13-year-old Berlin girl who was allegedly gang-raped by Muslim migrants. Moscow accused the German government of a cover-up, and it reached the level of Foreign Minister Lavrov lodging an official complaint about the case.

Inconveniently for the Kremlin, investigation revealed that the rape never actually happened. This is part of the long Russian tradition of disinformation, the peddling of half-truths mixed with fabrications for political effect, a key component of Mr. Putin’s Special War against the European Union and NATO. Germany today is fertile ground for such disinformation, since migrant crime is real, not a figment of the right-wing imagination, and lurid stories are assured clicks on the Internet. A Germany that is absorbed with mass migration and resulting societal instability—with Moscow having a hand in both—is a Germany that’s not focused on NATO and defending Europe from the Russians.

European security officials have accepted that Mr. Obama is unlikely to change course in the last months of his presidency. They are on their own facing Mr. Putin, or nearly so, for now. The KGB officer in the Kremlin can be deterred. In terms of population and economy, Russia is more or less Mexico with several thousand nuclear weapons. The urgent task at hand is preventing all-out war between Russia and the West by keeping the new Cold War cold. Since Cold War 2.0 is likely to last as long as Mr. Putin is in power, and he shows no signs of leaving the Kremlin soon, this is yet another avoidable foreign policy mess that Mr. Obama will bequeath to his successor.