In Brussels last Saturday for an emergency meeting of the European Union, Lithuanian President Dalia Grybauskaitè described Russia as “practically in a war against Europe.” Indeed, it’s no longer enough that Russia seems poised for a full-on war with Ukraine. In recent days, and with NATO leaders headed for a summit this week in Wales, the larger issue of security on the European continent has become far more urgent.

There are few lingering doubts as to Vladimir Putin’s eagerness to flex Russian muscle in regions once under the Soviet thumb. This week, Putin reportedly told a European official that he could “take Kyiv in two weeks” if he wanted. Earlier, on Aug. 27, a mass of Russian tanks, artillery and troops reportedly crossed into Ukraine—prompting Ukrainian President Petro Poroshenko to declare that the region was “close to a point of no return: full-scale war.” Two days later, Putin addressed an exuberant crowd at a pro-Kremlin youth camp near Moscow. He reminded his supporters: “Russia is one of the leading nuclear powers”—and warned everyone else: “It’s best not to mess with us.” The Ukrainian government responded with an announcement that it will reinstate mandatory army conscription throughout the country.

While Ukraine is not a NATO member, NATO leaders have responded. On Monday, officials announced that the alliance will create a “spearhead” rapid reaction force, comprised of up to several thousand troops, that could be dispatched to an Eastern European conflict zone in as little as two days (rapid reaction forces currently take five days to arrive on site)—and would be supported by military equipment stockpiles, stored at alliance bases in the region. The unit, said NATO Secretary-General Anders Fogh Rasmussen, would “travel light, but strike hard.” Days earlier, Britain and a coalition of six NATO allies agreed to create a “joint expeditionary force” of at least 10,000 soldiers (as well as air and naval units), which would boost NATO’s power in the event of a crisis in the region.

Meanwhile, angst mounts in what Russian officials often term their “near abroad.” In August, Polish Prime Minister Donald Tusk told reporters that he had “reason to believe that the threat of a direct intervention” was growing. Nearby, the Baltic states of Estonia and Latvia—which boast large Russian-speaking populations—worry about falling victim to the so-called Putin Doctrine, by which Russia claims a right to protect ethnic Russians it deems threatened, in whatever sovereign nation they might live. As Polish Foreign Minister Radoslaw Sikorski once famously observed: “Russia has never actually invaded Poland—instead it always ‘came to help.’ ”

NATO’s Rasmussen last week described the Ukraine crisis as a “wake-up call” for the alliance. At the summit this week, NATO leaders are expected to agree, for the first time, on significant military deployments to new bases in eastern member states: Lithuania, Latvia, Estonia and Poland, which are pleading for NATO boots on the ground. NATO leaders are also expected to discuss a re-establishment of large-scale military exercises in central and Eastern Europe.

It was not supposed to be this way. In 1997, less than a decade after the Soviet Union crumbled, the newly emerged Russian Federation struck a deal with the North Atlantic Treaty Organization—the alliance set up after the Second World War, in large part, to contain the Soviets. Under the 1997 NATO-Russia Founding Act, each side agreed not to “consider each other as adversaries.” For its part, NATO went a step further, promising no “additional permanent stationing of substantial combat forces” in the former Soviet sphere. For nearly two decades, this “geopolitical quarantine” held.

But a new battlefield Europe has been taking shape. On Aug. 27, Finland—which shares a long border with Russia, but which has never joined NATO—signed an agreement with the alliance that will make it easier for NATO to station troops on its soil. That same day, Russia’s permanent mission to NATO promised—vaguely, and via Twitter—that Moscow will react “with a view to ensure its security.”

Some critics contend a NATO ramp-up will only inflame Russia and make things worse in Europe. Others doubt the alliance’s ability to maintain a credible threat posture vis-à-vis Russia—especially given falling defence expenditures in most NATO member states. An August report by the U.K. House of Commons concludes: “NATO is currently not well-prepared for a Russian threat against a NATO member state.” “The Western response overall has been slow, small and late,” says John Herbst, the former U.S. ambassador to Ukraine, in an interview with Maclean’s. Western leaders “set what seem to be red lines, but when Putin crosses those red lines, they’re sidelined.” Despite belated NATO manoeuvring, says Herbst, Putin clearly “feels emboldened.”

Others still lament that while Ukraine was the inspiration for NATO’s push to mobilize, NATO heavyweights like the U.S. have thus far refused to offer military aid to Kyiv. Last week, U.S. President Barack Obama restated his “unwavering commitment to Ukraine and its people”—but affirmed, “We are not taking military action to solve the Ukraine problem.” Instead, NATO leaders will discuss the possibility of further economic sanctions against Russia. Depending on one’s view of things, Obama’s reticence is either a wise display of caution or an abandonment of Ukraine and, in turn, an indication that NATO will be more tempered going forward than its rhetoric suggests.

The issue of Ukraine’s relationship to the alliance is all the more pressing following Friday’s announcement from Ukrainian Prime Minister Arseniy Yatsenyuk that it will seek full NATO membership. In that case, “we will get a new Cold War,” says Lord David Owen, a former British foreign secretary and a former EU peace negotiator in Yugoslavia. “But it will be a very different Cold War this time.” No longer so isolated, Russia, he adds, is finding it easy to work with China, Japan and Turkey. Owen is in favour of EU membership for Kyiv, but thinks admitting Ukraine into NATO is against the alliance’s strategic interest. “Wars are started when people feel beleaguered and encircled. That’s the history of the 1914 war and we ought to understand that.”

NATO members have, nevertheless, taken steps to fortify the alliance’s defence posture. On a trip to Poland in early June, Obama announced plans for a nearly $1-billion European Reassurance Initiative (ERI), which would enable a bigger U.S. military presence in central and Eastern Europe. The announcement capped off an active spring season. In May, some 6,000 allied forces participated in “Steadfast Javelin 1”, a military drill in Estonia designed to repel an attack on the Baltic region. Around that time, NATO tripled its Baltic Air Policing Mission, began aerial surveillance flights over Poland and Romania and deployed two new NATO maritime groups to patrol the Baltic and Mediterranean seas. (On Monday, Canada’s Air Task Force joined the Baltic Air Policing mission with four CF-188 Hornet aircraft and over 130 personnel from the Royal Canadian Air Force.)

This is surely in recognition that Russia has spent the last few years bulking up its own military. In 2010, Moscow launched a massive 10-year weapons modernization scheme, estimated to cost a staggering $720 billion. “We have seen the Russians improve their ability to act swiftly,” acknowledged NATO’s Rasmussen, in August. “They can within a very, very, short time convert a major military exercise into an offensive military operation.” Even those who believe that Putin lacks the chutzpah to invade a NATO member fear Russia’s adeptness at launching cyber-attacks, propaganda campaigns and its ability to funnel support to pro-Russia rebels.

The strength of NATO is rooted in Article 5 of the treaty, which says that “an armed attack against one or more [members] shall be considered an attack against them all.” Yet over the years the goal of collective defence changed and NATO became more political in orientation. It began to busy itself in conflicts far and away, like Bosnia and Afghanistan. In 2002, the NATO-Russia Council was created to facilitate “consensus-building, and alliance leaders began to speak of Moscow as a “strategic partner.”

The alliance grew to 28 nations, with a large influx in the late ’90s after a long and tense debate within NATO about the wisdom of admitting former Soviet states. In 1999, the Czech Republic, Poland and Hungary signed on. In 2004, Lithuania, Latvia, Estonia, Romania, Slovakia, Slovenia and Bulgaria joined too. All the while, a wary Russia watched on. In 1995, Russian President Boris Yeltsin warned that “when NATO comes right up to the Russian Federation’s borders . . . The flame of war could burst out across the whole of Europe.” When Ukraine applied to join NATO’s “Membership Action Plan” in 2008, Russia’s deputy foreign minister called the possibility “a huge strategic mistake that would have most serious consequences.” Membership talks were shelved in 2010.

Today German Chancellor Angela Merkel heads NATO’s hold-back lobby. Merkel—who speaks Russian and has reportedly spoken to Putin dozens of times since Russia entered Crimea—has continued to oppose talk of building new bases in Eastern Europe. (The only NATO base east of the old Iron Curtain is on Poland’s Baltic coast, in the city of Szczecin.) But Merkel can hardly silence calls for help from Russia’s ex-satellites. When the three Baltic states of Estonia, Latvia and Lithuania achieved independence in 1991, they were left with virtually no military capability. Their forces remain small—and so, in their view, Baltic territorial integrity remains uncertain. In June, Lithuania’s president told the German magazine Focus that Russia had offered to reduce gas prices in Estonia and Latvia if the countries agreed to ditch their NATO membership.

But if Europe is to become battle-ready, it will surely happen first in Poland. Poland, too, has renewed calls for a permanent NATO presence, recently requesting that two NATO brigades (about 10,000 soldiers) be deployed forthwith. The request was denied. In the meantime, Warsaw has been steadily acquiring military equipment as part of a modernization scheme that will reportedly cost $45 billion by 2020. It is speeding up its planned purchased of 30 attack helicopters and reportedly working to acquire a new cache of long-range attack drones.

Warsaw has no shortage of motivation to act fast. The Russian threat is real and close to home. On Monday, Kyiv reported that pro-Russia rebels had made significant gains in the eastern Ukrainian city of Luhansk, where government forces were forced to abandon the airport. Ukrainian military spokesperson Andriy Lysenko claimed that the rebels were supported by “a Russian tank battalion.” Western analysts estimate that over 1,000 Russian troops are fighting alongside Ukraine’s pro-Russia separatists in a conflict that has, since mid-April, killed around 2,600 people.

Last weekend, retired U.S. Army general Wesley Clark, who served as NATO’s supreme allied commander in Europe from 1997 to 2000, referred to the Wales summit as “the best, and perhaps last, opportunity to halt aggression in Europe without major commitments of NATO forces.”

Still, if Rasmussen has his way Europe will soon be a changed continent. His supporters believe the NATO chief will follow through on his tough talk—and will find a way to bring detractors like Germany around. One possibility is that NATO leaders will not use the vocabulary of “permanent” forces—but will instead pledge “temporary” and rotating forces whose terms of use are as-of-yet unlimited. “The bottom line,” says Rasmussen, “is you will, in the future, see a more visible NATO presence in the East.”

Olga Oliker, a senior international policy analyst at the Rand Corporation, argues there are some substantive differences between “permanent basing” and this lesser step. For starters, “it doesn’t send the same signals,” both to Russia and to its ex-satellites. Moreover, temporary basing might be easier for NATO leaders to sell to their electorates. Either way, it seems likely that former Soviet states will soon enjoy a wash of NATO troops and equipment.

Intentions or language aside, the formation of an armed-and-ready Europe will not prove easy. For one, it’s expensive. Last year, just four NATO members reached the alliance’s target defence-spending goal of two per cent of GDP. Canada was one of the alliance’s biggest defence cutters, slashing spending to just over one per cent of GDP, down from 1.4 per cent in 2009. Last week, Reuters reported that Canada planned to block NATO’s appeal for member states to increase defence spending. Canada has thus far dispatched two dozen personnel to NATO’s Supreme Headquarters Allied Powers Europe (SHAPE), assigned six fighter jets to regional air patrol missions, provided non-lethal military aid to Ukraine, dispatched the HMCS Toronto frigate to the Mediterranean Sea and offered Kyiv $220 million in loans and loan guarantees. Foreign Affairs Minister John Baird recently declared that he will push for “additional measures” against Russia. (He declined to elaborate on the nature of those measures).

The U.S., by contrast, carries far more than its weight, contributing 72 per cent of NATO’s defence spending, up from 63 per cent in 2001. (NATO’s International Security Assistance Force [ISAF] is sometimes jokingly referred to as “I Saw Americans Fighting.”)

There’s also the complicated issue of economic interdependence between Russia and Europe. Russia needs European export markets while a number of European states are energy-reliant on Moscow. Over a third of the EU’s oil is of Russian origin. Russia supplies the vast majority of natural gas consumed in Slovakia, Hungary and Poland (84, 80 and 59 per cent respectively). And more than half of Russian gas transports to the continent arrive via pipelines through Ukraine.

Meanwhile, the fundamental question remains: will NATO growth thwart Russia or merely prod the bear? In a widely read article in Foreign Policy, international relations scholar John J. Mearsheimer argues that crisis in Europe “is the West’s fault.” In this view, NATO has boxed Russia in. Mearsheimer cites not only hard military expansion, but also Western civil society projects that seek to “spread Western values and promote democracy” in post-Soviet States. By this logic, NATO would be better advised to back away from the former Soviet Union. Other critics warn that Moscow’s co-operation is urgently needed in other areas of NATO and U.S. concern: namely, Afghanistan and Iran.

The counter-claim to Mearsheimer’s is that if NATO had acted sooner, the crisis in Ukraine could have been averted. John Herbst, the former Ukraine ambassador, believes that NATO has consistently failed to meet Russian aggression with sufficient fortitude. He points to 2007, when Estonia fell victim to a large-scale cyberattack that is widely believed to have originated in Russia. And 2008, when Russia invaded Georgia. And March 2014, when Russia’s annexation of Crimea was quickly accepted as a fait accompli. Sanctions earlier on, argues Herbst, “might have averted the shoot-down” of Malaysia Airlines Flight MH17.

Much of the debate around Ukraine has focused on how Russia might be contained or cajoled, but Britain’s Lord Owen argues that NATO must also take a firm line with Ukraine’s leadership. He is not alone in arguing that tumult in Ukraine will only cease if Ukrainian President Poroshenko agrees to form a devolved government in east Ukraine— a federal structure that goes “as far as Quebec” and incorporates strong Russian-language protections. Russia has called for full-scale devolution, but Poroshenko has thus far resisted.

On Tuesday, 48 hours before the Wales summit, Russia hinted at a policy shift. Mikhail Popov, a Kremlin adviser, told Russian state media that NATO was “aggravating tensions with Russia”—and that its enlargement plans posed “existential threats” to Moscow. Though he declined to offer details, Popov vowed that Russia, too, would adjust its military doctrine in the central and Eastern European region where it once ruled supreme. Perhaps Moscow is already fine-tuning that doctrine with its border ally Kazakhstan. Before a small audience in Russia on Friday, Vladimir Putin called Kazakhstan’s statehood into question—and referred to the country as “part of the large Russian world.” The comments echo those made by Putin in 2008 when, at a summit in Bucharest, he told former U.S. president George W. Bush that “Ukraine is not even a state.” He seems more intent than ever to prove his point.