Those who argue for more democracy in the European Union to give the leaders in Brussels real legitimacy and force them to justify their decisions publicly face two big hurdles.

The first is the determination of national Parliaments to hold on to what remains of their powers. As it is, two-thirds of legislation is approved in Brussels and then passed to the national Parliaments to nod through. No wonder that German lawmakers are so exercised about the euro crisis.

The plan, vaguely outlined by Mrs. Merkel and Mr. Sarkozy after they met in Paris last Tuesday, to introduce economic governance on the E.U. level would mean Brussels encroaching on Germany’s national budgets and tax systems. Such governance is a logical step toward more economic integration. But, ask lawmakers, where is the democratic accountability and transparency? Mr. Habermas says it does not exist.

The second hurdle is that more democracy would mean reopening the E.U. treaties, which, among many other things, set out how the leaderships in Brussels are chosen and how the institutions function.

“This is a big problem for legitimacy. If you want to seek more legitimacy through legitimate means, then that means amending the treaties,” said Krzysztof Bledowski, a European expert and economist and council director of the Manufacturers Alliance, a lobby based in Arlington, Virginia, that keeps a close eye on developments in Europe.

But no E.U. leader wants to reopen the laboriously negotiated treaties.

The Union could at least be democratized in small ways. But, noted Mr. Swieboda, “the E.U. works on the basis of method, of processes. They take precedence over democracy.”

Momentous decisions like the introduction of the euro or enlargement are taken in tiny steps at first, making it difficult for opponents to garner enough public support at any given moment. But once the process has gathered steam, it becomes even harder to stop. Both the Commission and the member states always put forward the argument that a rupture would be too risky and too costly. Besides, in the end, everyone will benefit from closer integration.