By DAN BILEFSKY
PARIS — Romania’s center-left government overwhelmingly won parliamentary elections, according to partial results released Monday, an outcome that threatened to push the country into further political upheaval because of bitter rivalry between the prime minister and the president.
The central electoral office said the center-left alliance led by Prime Minister Victor Ponta won about 59 percent of the seats in the 452-seat legislature, followed by about 17 percent for a center-right group linked to President Traian Basescu. Around 81.45 percent of the votes have been counted.
The clear victory in Sunday’s election made Mr. Ponta the front-runner for prime minister. But Mr. Basescu, who has the power to appoint a prime minister, has indicated that he would not select Mr. Ponta, in part because Mr. Ponta tried to have him impeached over the summer.
During the campaign, Mr. Basescu called Mr. Ponta a “compulsive liar” and an “ogre” and said that appointing the man who tried to oust him would be like swallowing a pig. Mr. Ponta’s coalition, in turn, threatened a new impeachment effort if it won a majority and Mr. Ponta was not named prime minister.
Analysts said Mr. Basescu could be forced to back down due to the large margin of the center-left’s victory, which made Mr. Ponta’s reappointment seem inevitable. As of Monday morning, the president had not announced his intentions.
If he refused to appoint Mr. Ponta, the standoff threatened to produce a protracted political fight that could destabilize the country, undermine its struggling economy and delay a loan deal from the International Monetary Fund that Romania is hoping to negotiate when its current arrangement expires early next year.
In Bucharest, the Romanian capital, political commentators called the election “Basescu’s revenge.”
“The most we can hope for is that it is not a long war, and the parties find a compromise,” said Cosmin Stan, a leading Romanian broadcaster with Realitatea Television.
Romania, a poor Balkan country that has struggled to shed the legacy of decades of dictatorship under Nicolae Ceausescu, has undergone some of its worst political turbulence in recent memory. The country has weathered a series of unstable governments and come under criticism from the European Union and the United States. In October, the European Commission, the union’s executive body, said that concerns about corruption and fraud had prompted it to block development aid potentially worth billions of euros. All the while, the public remains deeply disillusioned amid a simmering dissatisfaction with austerity — including a 25 percent cut in public sector wages — for which many voters blame Mr. Basescu.
Mr. Ponta, at 40 the youngest prime minister in the European Union, has been locked in a bitter power struggle with Mr. Basescu, a 61-year-old former sea captain. The acrimony was made worse by the July impeachment vote, which Mr. Basescu called a “coup d’état” and which drew sharp criticism from the European Union and the United States. Mr. Ponta had accused Mr. Basescu of overreaching his mandate by, among other things, refusing to appoint ministers chosen by the prime minister.
Many Romanians say they are tired of the dueling leaders, and in a sign of that discontent, the populist People’s Party of Dan Diaconescu, a flamboyant television station owner who campaigned in a white Rolls-Royce and is being investigated for fraud, won about 14 percent of the vote, according to the partial results. As part of his campaign, Mr. Diaconescu has promised around $26,000 to every Romanian who starts a business.
But the feud between Mr. Ponta and Mr. Basescu dominated the election.
Under the Constitution, the president must name a prime minister from the party that receives a majority, in consultation with the party. Mr. Ponta is the coalition’s choice. The candidate for prime minister then needs to be approved by the Parliament, where Mr. Ponta’s center-left coalition has won a strong majority. While the Constitution gives the president the prerogative to name the prime minister, he cannot ignore the popular vote.
Mr. Basescu could try to bypass Mr. Ponta by appointing another candidate from the center-left coalition. But constitutional specialists said Mr. Basescu’s room for maneuver was severely circumscribed now that Mr. Ponta’s coalition had such a clear mandate.
Some experts said that Mr. Basescu was banking on the fact that the Constitution says the president must appoint the prime minister from the winning party but is unclear on whether this applies to a coalition like Mr. Ponta’s. The Constitution is open to interpretation, and each side is interpreting it in its own interests.
Catalin Ivan, a spokesman for Mr. Ponta’s coalition, the Social Liberal Union, said that if Mr. Basescu did not appoint Mr. Ponta as prime minister, he would face an impeachment vote as well as Europe-wide condemnation. “We would like to think we have democracy in Romania,” Mr. Ivan said.
Cristian Parvulescu, the dean of political science at the National School of Political Studies and Public Administration in Bucharest, said that under the Constitution, Mr. Basescu was obligated to appoint a prime minister from the party that won a majority. While Mr. Basescu can reject the candidate put forward by the winner, Mr. Parvulescu said, such a move could put him on shaky constitutional grounds.
Laura Stefan, a legal specialist at Expert Forum, an independent research institute in Bucharest, argued that it was Mr. Ponta’s political immaturity that had plunged Romania into crisis and that Mr. Basescu was within his legal right to choose someone more qualified. She noted that two failed attempts to form a government within 60 days of Mr. Basescu’s first nominating a candidate would prompt early elections.
“It is clear that Mr. Basescu doesn’t like or trust Mr. Ponta, and so we are entering a period of uncertainty,” Ms. Stefan said. “But I don’t think anyone wants more political upheaval or early elections, and my prediction is there will be a hard-fought compromise.”
Analysts said that the poisonous atmosphere in Romanian politics showed little sign of abating, given that whoever became prime minister would have to try to work with Mr. Basescu, whose mandate ends in 2014. “We are in for a long political struggle,” Mr. Stan said.
George Calin contributed reporting from Bucharest, Romania.