The European Union is dying -- not a dramatic or sudden death, but one so slow and steady that we may look across the Atlantic one day soon and realize that the project of European integration that we've taken for granted over the past half-century is no more.

Europe's decline is partly economic. The financial crisis has taken a painful toll on many E.U. members, and high national debts and the uncertain health of the continent's banks may mean more trouble ahead. But these woes pale in comparison with a more serious malady: From London to Berlin to Warsaw, Europe is experiencing a renationalization of political life, with countries clawing back the sovereignty they once willingly sacrificed in pursuit of a collective ideal.

For many Europeans, that greater good no longer seems to matter. They wonder what the union is delivering for them, and they ask whether it is worth the trouble. If these trends continue, they could compromise one of the most significant and unlikely accomplishments of the 20th century: an integrated Europe, at peace with itself, seeking to project power as a cohesive whole. The result would be individual nations consigned to geopolitical irrelevance -- and a United States bereft of a partner willing or able to shoulder global burdens.

The erosion of support for a unified Europe is infecting even Germany, whose obsession with banishing the national rivalries that long subjected the continent to great-power wars once made it the engine of integration. Berlin's recent reluctance to rescue Greece during its financial tailspin -- Chancellor Angela Merkel resisted the bailout for months -- breached the spirit of common welfare that is the hallmark of a collective Europe. Only after the Greek crisis threatened to engulf the euro zone did Merkel override popular opposition and approve the loan. Voters in local elections in North Rhine-Westphalia promptly punished her party, delivering the Christian Democrats their most severe defeat of the postwar era.

Such stinginess reflects the bigger problem: Germany's pursuit of its national interest is crowding out its enthusiasm for the E.U. In one of the few signs of life in the European project, member states last fall embraced the Lisbon Treaty, endowing the union with a presidential post, a foreign policy czar and a diplomatic service. But then Berlin helped select as the E.U.'s president and foreign policy chief Herman van Rompuy and Catherine Ashton, respectively, low-profile individuals who would not threaten the authority of national leaders. Even Germany's courts are putting the brakes on the E.U., last year issuing a ruling that strengthened the national Parliament's sway over European legislation.

This renationalization of politics has been occurring across the E.U. One of the starker signs of trouble came in 2005, when Dutch and French voters rejected a constitutional treaty that would have consolidated the E.U.'s legal and political character.

The Lisbon Treaty, its watered-down successor, was rejected by the Irish in 2008. They changed their minds in 2009, but only after ensuring that the treaty would not jeopardize national control of taxation and military neutrality.

And in Britain, May elections brought to power a coalition dominated by the Conservative Party, which is well known for its Europhobia.

Elsewhere, right-wing populism is on the upswing -- a product, primarily, of a backlash against immigration. This hard-edged nationalism aims not only at minorities, but also at the loss of autonomy that accompanies political union. For example, Hungary's Jobbik Party, which borders on xenophobic, won 47 seats in elections this year -- up from none in 2006. Even in the historically tolerant Netherlands, the far-right Party for Freedom recently won more than 15 percent of the vote, giving it just seven fewer seats than the leading party.

If these obstacles to a stable union weren't sobering enough, in July, the E.U.'s rotating presidency fell to Belgium -- a country whose Dutch-speaking Flemish citizens and French-speaking Walloons are so divided that, long after elections in June, a workable governing coalition has yet to emerge. It speaks volumes that the country now guiding the European project suffers exactly the kind of nationalist antagonism that the E.U. was created to eliminate.

The renationalization of European politics is a product, first and foremost, of generational change. For Europeans who came of age during World War II or the Cold War, the E.U. is an escape route from a bloody past. Not so for younger Europeans: A recent poll revealed that French citizens over 55 are almost twice as likely to see the E.U. as a guarantee of peace as those under 36. No wonder new European leaders view the E.U.'s value through cold cost-benefit calculations, not as an article of faith.

Meanwhile, the demands of the global marketplace, coupled with the financial crisis, are straining Europe's welfare state. As retirement ages rise and benefits dwindle, the E.U. is often presented as a scapegoat for new hardships. In France, for example, anti-Europe campaigns have focused ire on the E.U.'s "Anglo-Saxon" assault on social welfare and on the "Polish plumber" who takes local jobs because of the open European labor market.