Even if the cabinet remains, analysts said the government’s collapse would undermine principal foreign policy aims of Mr. Topolanek’s coalition, including plans for construction of a United States missile defense installation in the country, which is already under review by Washington. This month, the Czech government temporarily withdrew treaties on the installation from the parliamentary ratification agenda in the face of an opposition threat to vote them down.

Karel Schwarzenberg, the foreign minister, sought to play down the significance of the vote, saying the opposition’s attempts to score political points would backfire.

“Paroubek is convinced that attacking the whole time is the best tactic and that will help him win elections,” he said in an interview before the vote. “But the Czech people don’t like it and would prefer that we have a cease-fire when we have the presidency of the E.U.”

He emphasized that even with the no-confidence vote, under the Czech Constitution, the prime minister and his top ministers could stay on until after the Czechs’ presidency of the European Union ends in June. “Our work as president of the E.U. will go on anyway,” Mr. Schwarzenberg said. “Our European partners will see at the next E.U. conference that we are all there.”

Analysts noted that although the Czech vote had been spurred by political infighting, it would nevertheless have the effect of undermining the Czech economy by unsettling already jittery foreign investors.

Political analysts said one of the greatest beneficiaries of the crisis could prove to be Mr. Klaus, an outspoken economic liberal, who is skeptical of the European Union. He founded the Civic Democratic Party of Mr. Topolanek, but in recent months he has criticized the prime minister for being too fervent an advocate of greater European integration, and he recently resigned as honorary chairman of the party.

Under the Constitution, as president he has to designate a new prime minister, making him the new kingmaker in Czech politics.

“Klaus is the big star when the government fails,” said Adam Cerny, a commentator for the newspaper Hospodarske Noviny, referring to the president. “With Topolanek as a lame-duck prime minister, he and his controversial views will once again be back in the spotlight.”