"He's the greatest gift to NATO since the end of the Cold War," former director of the US Central Intelligence Agency David Petraeus says of Russian President Vladimir Putin. "He set out to make Russia great again; what he's really done is make NATO great again by his actions," Petraeus told DW. "That threat has unified NATO in a way it hasn't been since the [Berlin] Wall came down and the Warsaw Pact and the Soviet Union dissolved."

But if the 30-member alliance is benefitting from the shared threat assessment, it's also being scrutinized as to how it responds to Russia's decision to order troops into Ukraine, in what the US has called the launch of a war. While NATO has no obligation to militarily defend non-member Ukraine, allies feel a sense of moral duty to uphold Ukrainian sovereignty and international law, even if that's from afar, since no other country has agreed to put boots on the ground in case of attack.

When it comes to alliance territory, NATO Secretary-General Jens Stoltenberg emphasizes reinforcement measures have been taken. "We have over 100 jets at high alert and there are more than 120 allied ships at sea," he said Tuesday, "from the high north to the Mediterranean. We will continue to do whatever is necessary to shield the alliance from aggression."

In response to Putin's recognition of Ukraine's breakaway regions of Donetsk and Luhansk earlier this week and his decision to send more forces into eastern Ukraine, the US added a thousand more troops to its already bolstered presence in the Baltics.

Speaking from Estonia, Kadri Liik, a senior fellow at the European Council on Foreign Relations, welcomed the move. "I don't think there is a direct threat to the Baltic states right now," she told DW before Putin's overnight announcement of what he called a "military operation" into Ukrainian-controlled territory . "But at the same time, the situation is nervous. If we are going to see a large-scale war in Ukraine in the coming days or weeks then, of course, that would make the situation much more tense in all the surrounding countries and also it would increase the danger of misreadings and accidental clashes on all fronts."

Lute: Show the show of force

But while it largely falls to individual allies to decide what they can contribute to NATO's eastern flank, not everyone thinks the alliance is maximizing its joint resources. "Where's the VJTF?!" exclaims former US ambassador to NATO Doug Lute, referring to the very high-readiness element of the NATO Response Force (NRF), comprising a bit under half the alliance's 40,000-strong rapid-reaction capability. "If it's the 'spearhead,' as [the NATO secretary general] calls it," Lute explained, "then it's time to form the spearhead!”

The retired three-star general, who has also served as the US deputy national security advisor for Iraq and Afghanistan, Lute believes NATO should immediately assemble the force — made up of land, air, maritime and special operations components. It could be set up somewhere in Europe now, he said, for quick deployment if and when needed. While the VJTF would only be deployed in case of a threat to an ally, "there's the potential for conflict in Ukraine to have spillover effects onto NATO territory," Lute warned. "If you have such a force, and in this instance, a crisis of a generation… if you don't use it or you don't at least display it, then you really don't have a force."

Spillover to cyberspace

One of the spillover effects could come from cyber attacks, which Ukraine has been experiencing intensively in recent days, and against which NATO has been working with Kyiv for years. Colin Clarke, director of research at the Soufan Center, emphasizes it's critical to build up that resilience. "I think the priority for Ukraine at the moment should be anticipating areas where the Russians might launch a cyberattack," he said, adding that means "Tier 1 targets should receive extra attention in terms of active cyber defense, especially critical infrastructure."

Clarke says while cyber-attacks are often seen as separate from military action, "it behooves Ukraine to conceptualize Russia's capabilities as a broad portfolio, with cyber just one of many tools at Moscow's disposal." He adds that "information warfare" is a "critical enabler" for the Kremlin, and urges the Ukrainian government to remind its people that "Russia will be highly active in the coming days and weeks in the 'gray zone' and to be on guard against a range of mis-, dis-, and mal-information narratives."

What's got to give?

On Wednesday, Ukraine's closest European Union and NATO neighbors, Lithuania and Poland, launched an appeal to bring Kyiv closer, urging an immediate offer of EU candidate status to Ukraine.

In a trilateral statement, the presidents of the three countries stated that "given the significant progress in the implementation of the Association Agreement and internal reforms, as well as the current security challenges, Ukraine deserves EU candidate status and the Republic of Poland and the Republic of Lithuania will support Ukraine in achieving this goal."

At the same time, however, Michael Bociurkiw, a senior fellow with the Washington, DC-based Atlantic Council, says Ukrainians are wondering whether they should concede to Putin's demands to give up their hopes to join NATO.

Ukraine's ambassador to the UK mentioned the idea in an interview with the BBC in recent days and while it was quickly walked back. Bociurkiw, who is currently in Lviv, Ukraine, says the statement was no accident.

"I think (Ukrainian officials) were floating that idea" he concludes, and he says some of the people he's talked with say "if that's what it takes to avert war, maybe we should do it." Bociurkiw says this would only be seriously considered by Kyiv if pressure comes from NATO itself to give Russia this off-ramp from the crisis.

"On one hand, you to talk to people here who say, 'if that ever happens, people will be out on the streets,'" he says, "but I'm not so sure about that anymore. I think the main thing people want to avoid right now is all-out war."