Calin Diaconu

The acrimony has dashed the high hopes that accompanied the electoral victory of the 40-year-old Mr. Ponta, who promised to usher in generational change in a country that has struggled to overcome one of the harshest Communist legacies among the former Soviet bloc states.

The two men are now locked in an uncomfortable cohabitation until elections in December, leaving this poor Balkan nation adrift. And even that vote, analysts say, may prove inconclusive.

In an interview at the gargantuan and opulent 1,100-room Palace of Parliament, built by the former Communist dictator Nicolae Ceausescu as a monument to his authority and grandeur, Mr. Ponta acknowledged mistakes but fell short of expressing outright regret.

He could barely conceal his contempt for Mr. Basescu, a former ship captain, whom he accused of brazenly clinging to power despite having been rejected by a majority of Romanians, calling the president politically “illegitimate.”

“My mentality as a new generation of politician is to respect the institution even if I don’t respect the person,” he said. “He will never give up. He is a former sea captain, and you won’t see a former sea captain being humble or giving up.”

Romania’s troubles have added to concerns in the United States and Europe about the political instability and threats to democratic institutions that are intensifying across the former Communist bloc.

In Hungary, Prime Minister Viktor Orban has come under criticism for flouting democracy with a series of measures that have brought the judiciary and the news media to heel. In the Czech Republic, the government has teetered on the edge of collapse with ministers involved in corruption scandals.

Romania, in particular, lacked a history of stable, enlightened governance even before it endured World War II and then decades of the Ceausescu dictatorship, which ended with his violent overthrow in 1989.

Since then, Romanians have labored to build democratic structures virtually from scratch, finding themselves in a far more challenging position than almost any of their post-Communist neighbors. Romania’s foibles have provoked debate about whether it and Bulgaria, which both entered the European Union in 2007, were invited too soon, before their cultures of lawlessness, corruption and winner-take-all politics had been uprooted.

The vociferousness of the domestic battle in Romania has overshadowed policy-making; rattled the currency, the leu; and undermined investor confidence in a country that is the second poorest in the European Union after Bulgaria.

Mr. Ponta’s government has issued more than two dozen emergency decrees — moves that, while legal, have alarmed Western diplomats and many Romanians. The government dismissed the speakers of both chambers of Parliament, which the opposition said was unconstitutional. And amid accusations that it was pressuring the Constitutional Court, the government ousted the ombudsman, who has the power to challenge emergency legislation before the court.

Some members of the progovernment media have accused foreign journalists of being anti-Romanian agents. The public remains largely disgusted with endemic graft and corruption. Adding to the mistrust are accusations that Mr. Ponta, a former prosecutor, plagiarized parts of his doctoral thesis. (He says the accusations were politically motivated, but an academic panel at the University of Bucharest, where he was awarded the Ph.D. in 2003, upheld them. Yet, he has not been stripped of his title.)

Romania’s mercurial president has also played a key role in fomenting crisis.

The move for impeachment was prompted by accusations from the government that Mr. Basescu had overreached his mandate by, among other things, refusing to appoint ministers chosen by the prime minister, pressuring prosecutors in legal cases and using the secret services against enemies.

Mr. Basescu, who has denied the accusations, accused Mr. Ponta — already being criticized for abusing the system of parliamentary checks and balances — of orchestrating a “coup d’état.”

Mr. Ponta said his main shortcoming had been to not effectively communicate the reasons behind the impeachment vote. To repair the nation’s image, Mr. Ponta said, he was studiously avoiding confrontations with the president, and had recently removed himself from an acrimonious meeting about foreign policy to avoid another public and damaging altercation.

“Our European and American partners appreciate stability and predictability, and the lack of these two leads to overreaction and misunderstanding,” Mr. Ponta said, explaining the lessons he has learned since becoming prime minister.

Mr. Basescu declined an interview request, in keeping with the conspicuously low profile he has maintained since the referendum on his impeachment, which was favored by an overwhelming majority in July, even though the turnout of 46 percent was below the 50 percent needed to make the vote valid.

Western diplomats were so concerned in August that the country was teetering toward lawlessness that in August, Washington dispatched Philip H. Gordon, the assistant secretary of state for European and Eurasian affairs, to Bucharest, where he met both men and warned that Romania must uphold the rule of law.

Chancellor Angela Merkel of Germany and José Manuel Barroso, the European Commission president, have also voiced concerns. Talks on Romania’s bid to join the European Union’s coveted visa-free zone, scheduled for September, were postponed.

Romania has to “remove all doubts on its commitment to the rule of law, the independence of the judiciary and the respect for constitutional rulings,” Mr. Barroso warned Mr. Ponta last month in Brussels.

Monica Macovei, a former minister of justice and close ally of Mr. Basescu, argued in an interview that the breaches of the rule of law in the run-up to the impeachment referendum were worse than anything since the Ceausescu era, referring to the government’s measures to consolidate its power.

But she insisted that Romania’s membership in the European Union had been instrumental in overcoming the political showdown. The European Union closely monitors Romania’s justice system and also gives Bucharest much-needed financing. That gives Brussels significant leverage over the country.

“We joined the E.U. to follow the rules, not to destroy them,” she said.

There is little indication, however, that the political tumult will end soon. Mr. Ponta’s leftist coalition is expected to do well in the December elections, analysts say, but may fall short of winning a majority. Voters appear even more disenchanted with Mr. Basescu and his rightist party, which they associate with punishing austerity measures.

More than anything, the relentless sparring and stalemate have engendered deep disappointment among Romanians in the promise of their young democracy and disillusionment with their political leadership.

“Our politicians behave like children fighting over a toy,” said Monica Cristea, 43, a manicurist from Poenari, a village near Bucharest. “They have destroyed our international reputation,” Ms. Cristea said. “I am outraged. I don’t like any of them. I don’t trust them.”

(A version of this article appeared in print on October 20, 2012, on page A3 of the New York edition with the headline: Symbol of Romanian Leadership? Hands on a Throat.)