For many Europeans, Russia is now deemed an authoritarian peril threatening their eastern flank, whose weapons of choice are 1930s-style land grabs, troop buildups, crude propaganda and political sabotage. A 20-year-old concept of cooperation has shattered.
'We have come from a period where we saw Russia as a partner... We are now in a very, very different time, and I think individual nations need to take this aboard and consider,' NATO's top military commander, US Air Force General Philip Breedlove, declared this week. He described it as a 'new paradigm' for Europe.
More and more voices are now being raised that accuse the EU of failing to rise to the challenge. They describe its response as weak, fragmented and tardy, reflecting unwillingness to make sacrifices and a dependence on the US to provide political muscle and military shield.
'Responding effectively to Putin's challenge will require more cohesion and determination than the EU has mustered. The risk of failure is considerable, and the potential consequences are grave," said Stefan Lehne of the Carnegie Endowment in Brussels. "Just as the EU mobilized for decisive action at the height of the euro crisis, it must now do so again."
Economic ties with Russia explain the EU's low-key sanctions package. EU trade with Russia is 10 times greater than US trade with Russia and there are powerful lobbies, notably in German industry and the City of London, which fiercely but discreetly oppose tougher penalties against business or financial assets.
The Group of Seven (G7) economies agreed this week to explore new sources of energy to prevent Russia from using oil and gas as a political weapon. But they also ruefully noted that the options were limited.
"I don't know anyone in the world who could tell us how Europe's dependency on importing Russian gas can be changed in the short term," sighed Germany's energy minister, Sigmar Gabriel, whose country buys around US$15 billion a year of gas from Gazprom.
The EU derives about a quarter of its gas needs from Russia, through commercial arrangements and infrastructure that date from the Cold War but were never changed.
"The mutual suspicions and anxieties associated with Cold War ideology merely adapted to the needs of a global economy and the more co-dependent nature of international relations," explained Sarah Lain at the Royal United Services Institute, a London thinktank.
Some analysts take a wider view of the EU's performance. They say that, in the early stages of a showdown, an authoritarian state is bound to act faster and more nimbly than a democracy. This is especially so when it comes to decision-making by 28 countries, who share authority with the EU's executive, the European Commission, and the Council of Ministers, which gathers governments.
"The hybrid system reveals again its limitations when faced with an agile realpolitik power like Russia," said Michael Emerson, a senior research fellow at the Centre for European Policy Studies (CEPS) thinktank in Brussels. "We are still stuck in the timewarp of only semi-concerted foreign policies at a time when a strongly united EU is needed."
French MP Philip Cordery, who is also a member of the National Assembly's Foreign Affairs Committee, said the EU had been dismissed time and again in past crises, but always bounced back.
"This is not the first challenge for Europe. There was the Cold War, the fall of the Berlin Wall, then there was the war in former Yugoslavia and now there is Ukraine. There are regular challenges for the European Union and the EU has overcome them every time," he said.
"I am quite confident we will overcome this problem with Ukraine. Among the European states there is unity on the issue even if there are some nuances. There is no clash like there was in the Iraq war between two member states with totally opposed opinions."
Cordery added that Europe's dependence on Russia could turn out to be a potent weapon. "Russia also needs to keep good relations with European states," he noted.