“We are seeing the end of the era of the giant and unquestioned names in Czech politics,” said Erik Tabery, a leading journalist. “The country is in a bad mood because of a feeling that more than two decades after the revolution, things should be better than they are.”

Although the Czech Republic has not suffered from the same sharp economic pain as the southern European economies, it has been buffeted by 9.4 percent unemployment, weak economic growth and a series of corruption scandals.

Against that backdrop, the avuncular and urbane Mr. Schwarzenberg has emerged as a conciliatory candidate of unexpectedly wide appeal. Yet he has several challenges to overcome, including his exile to Austria during the Communist period, which some critics, including Mr. Klaus, have seized on to dismiss him as a foreigner. Therese, his Austrian wife, does not speak Czech.

He himself still speaks the somewhat archaic Czech of his childhood and has been criticized for incoherence and for dozing off during debates. (His aides say he closes his eyes when faced with strong spotlights.)

That sort of haziness extends to his political career, in the minds of his critics, who portray him as a political opportunist who has flip-flopped between parties in the pursuit of power.

“He has been linked to three or four different parties on both left and right, from Greens to conservatives, in the aim of attaining high office,” said Tomas Jirsa, former vice chairman of a national conservative youth group. “Today he is a conservative, but who knows tomorrow?”