Romania's ruling majority has begun procedures to suspend President Traian Basescu after parliamentary speakers were sacked and the powers of top judges were curbed.
Lawmakers from the left-leaning Liberal Social Union (USL) have called an extraordinary session to debate impeaching the center-right president.
A vote is expected on July 6, and Basescu is due to attend the session.
If approved by parliament, Basescu's impeachment must be voted on in a referendum within 30 days.
Leftist Prime Minister Victor Ponta's cabinet has already issued a decree barring the Constitutional Court from ruling on parliamentary decisions, thus opening the door for the governing majority to impeach Basescu.
Ponta himself is under growing pressure to resign because of accusations of plagiarism.
The Constitutional Court was called to issue a "consultative" ruling on the motives invoked in the impeachment decision. The ruling on July 6 avoided making a clear recommendation for or against the impeachment.
But the Court issued a separate statement saying that one of its judges had been "threatened." No details were offered.
West Wants 'Stable' Romania
The court has filed an official complaint with the Venice Commission, the Council of Europe's advisory body on constitutional matters.
Both the European Union and United States have voiced deep concern about attacks on democracy in Romania.
EU President Herman van Rompuy said in a Twitter message on July 6 that he was "very concerned" about developments in Romania.
And European Commission President Jose Manuel Barroso has invited Ponta to Bruxelles next week to discuss the situation.
U.S. Ambassador to Romania Mark Gittenstein, in an Independence Day speech in Bucharest with Ponta standing by his side, warned about the importance of strong democratic institutions.
"The strength of these institutions," Gittenstein said, "will decide whether you prosper and whether your children will decide to even live here."
Gittenstein had earlier said Washington wants a stable Romania, where parts of its missile shield are to be installed.
Ponta's ex-communist Social Democrats (PSD) succeeded in suspending Basescu in May 2007, but he was overwhelmingly restored to office by a subsequent public referendum.
Basescu's approval rates, however, have plummeted since, in part because of drastic austerity measures his center-right allies imposed in 2010 in agreement with the European Union and the International Monetary Fund.
'Blitzkrieg' On Democratic Institutions
The last center-right government fell in May following a no-confidence vote, bringing Ponta's ex-communists and his liberal ally, the National Liberal Party (PNL), to power.
The opposition center-right speakers of both houses of parliament were sacked on July 3, prompting references in the Romanian media to a "blitzkrieg" against the country's fragile democratic institutions.
On the same day, Basescu likened the leftist government's actions to its crackdown on the opposition in 1990, when then-president Ion Iliescu, Ponta's mentor, summoned thousands of miners to Bucharest to attack pro-democracy protesters.
Basescu warned that the final goal of the government's drive to impeach him was to take control of the judiciary after former premier Adrian Nastase last month became the first high-profile politician to be sent to jail for corruption.
Romanian journalist and talk show host Robert Turcescu told RFE/RL that the independence of the judiciary poses the highest threat to Romania's corrupt politicians.
"The biggest gain of the past several years," Turcescu said, "is that the most important thing in a democracy -- the judiciary -- has become independent, and was allowed to self-regulate its working framework."
'Strong Reaction From Civil Society'
Romanian rights groups have sent an open letter to the European Commission saying that the rule of law was under "unprecedented attack" from the USL.
Journalist Robert Turcescu, however, says Romanians themselves must take action rather than complain abroad.
"As a citizen and journalist of this country, what I want is not to have to wait for the salvation to come either from the Americans or the European institutions when democracy is veering off the road in my country. What I want is a strong and firm reaction from the civil society," said Turcescu.
Meanwhile, hundreds of people on July 5 and 6 staged demonstrations in Bucharest and other cities in support of Basescu and against what they regard as the current threat to democracy.
With additional reporting by AFP and Reuters