This should have been a year of celebration in central and eastern Europe. It is 20 years since the Berlin Wall fell, the 10th anniversary of Nato's eastward expansion and five years after the European Union began its enlargement into the region: from the Baltic to the Black Sea, the countries that escaped from Soviet rule have much to commemorate.

But the global economic crisis has spoilt the party. Instead of building on the achievements of the past two decades, the region's leaders are feeling the economic foundations shaking under their feet.

All of Europe is heading towards its worst economic crisis since the 1930s. But compared with the wealthy west, central and east European nations are in a weaker position to respond. The dangers are so great that European Union leaders meeting in Berlin last Sunday agreed to back a doubling of International Monetary Fund resources to $500bn (£348bn, €391bn) to support the CEE countries in what Angela Merkel, German chancellor, called an “extraordinary international crisis”.

At risk is not only the economic development of vulnerable countries but even their political stability. Nobody expects a repeat of 1930s evils. But mounting anger over recession, unemployment and debt could fuel populism with unpredictable consequences. As in western Europe, there could be social and ethnic tensions. Reformist governments, multinational companies and banks could all become the targets of public protest when livelihoods are threatened. “The economic crisis will impact . . . eastern Europe more than western Europe because the political and economic systems in eastern Europe are more vulnerable,” says Carl Bildt, Sweden's foreign minister.

The EU itself, the region's political and economic lodestone, is running into trouble amid signs of western leaders responding to the crisis by putting national interests before Union-wide solidarity, notably over state aid for finance and industry. Having worked hard to bring their countries into the globalised European mainstream, some central and east European leaders feel betrayed. Pavol Demes, a former Slovak foreign minister and head of the CEE office of the German Marshall Fund, a US think-tank, says: “People are questioning liberal democracy, the markets and the EU. They see countries like France going for national solutions when international solutions are needed. They feel excluded.”

He and others applaud the Czech Republic, holder of the EU's rotating presidency, for challenging Nicolas Sarkozy, the French president, over suggestions that aid to France's carmakers might be tied to preserving French jobs rather than those the marques provide in central Europe. Mirek Topolanek, Czech prime minister, spoke for many in the CEE region when he said the response of eurozone countries “has deformed the joint project of the euro more than any other imaginable event”.

For all the anti-government demonstrations in Bulgaria and Lithuania, violent protests in Latvia and a surge in anti-Roma rhetoric in Hungary, however, CEE is not a region about to collapse into disorder. Despite the worries about EU solidarity, the 27-nation bloc's new members remain committed to enhancing their integration. Poland, for example, is accelerating plans to join the eurozone. “What we need is more Europe, not less Europe,” says Eugeniusz Smolar, head of Warsaw's Centre for International Relations.

Whatever happens, different countries are likely to go through the crisis with widely differing results. At one extreme are nations under particularly severe financial pressures, headed by Hungary, Latvia and Ukraine, which have secured IMF rescue packages. At the other stand Poland, the Czech Republic and Slovakia, a base of relative economic stability in the central European heartland. Manfred Wimmer, chief financial officer of Erste Group, the Austrian bank with big CEE operations, warns: “What's been lost in this crisis very often has been the ability of people to differentiate.”