Romania's Constitutional Court gave President Traian Basescu a fighting chance of beating a referendum aimed at ousting him, ruling on Tuesday, July 10 that at least half the electorate must turn out for the vote to be valid, Reuters said.

But the ruling Social Liberal Union (USL) said it considered a decree passed last week, stating there was no turnout threshold, still applied - setting up a further constitutional battle and likely condemnation from Europe and the markets.

The attempt by leftist Prime Minister Victor Ponta to unseat right-wing President Basescu has raised international concerns over rule of law in the European Union's second-poorest country.

Parliament last week approved a measure by Ponta's USL to suspend Basescu, saying he had overstepped his powers. An impeachment referendum will take place on July 29.

The Constitutional Court had been asked by the opposition to rule on the legality of a new law which would have made it easier to vote Basescu out - requiring only a majority of those voting in a referendum to impeach the president, rather than a majority of the whole electorate as was the case previously.

While the court ruled on Tuesday that the law was constitutional, it also said that turnout must be more than 50 percent of the electorate for the referendum to be valid - effectively nullifying the law's impact and giving the unpopular Basescu a chance.