The European Commission has called on Romania to respect the legal procedure to reinstate Traian Basescu as president.
The US says Tuesday’s Constitutional Court ruling “speaks for itself” in invalidating last month’s referendum to impeach him, because turnout fell short of the required 50 per cent of the electorate.
The move to oust Basescu had raised concerns in the West about the rule of law in Romania.
The leftist government said it would accept the decision but tensions remain.
“We find this Constitutional Court decision unfair as it ignores 8,5 million Romanian votes… a real majority,” said the acting President Crin Antonescu, calling Basescu an “illegitimate” leader.
But after the court’s ruling, parliament is expected to approve his return to office on Friday.
The 60-year-old political veteran who has been president since 2004 has appealed for unity.
One of the EU’s poorest states, Romania faces tough austerity demands from international lenders.
“I want to send a signal of stability to Romanians:
the Constitutional Court decision will be respected and implemented,” said Prime Minister Victor Ponta.
But few expect the bitter rivalry between the two adversaries to subside.
Tuesday saw small demonstrations in Bucharest’s two main squares: one crowd protesting against Basescu, another supporting him.
Many more are expected ahead of parliamentary elections later this year.