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.”