BUCHAREST (Reuters) - President Klaus Iohannis on Thursday called a national referendum for May 26, seeking to thwart a drive by Romania’s ruling Social Democrats (PSD) to weaken anti-graft legislation.

FILE PHOTO: Romanian President Klaus Iohannis arrives at a European Union summit in Brussels, Belgium March 22, 2019. REUTERS/Yves Herman/File Photo

Thousands of Romanians protested across the country last month after the PSD government passed an emergency decree that critics said chipped away at prosecutors’ independence in one of the European Union’s most corrupt states.

Approved without public debate, the decree was the latest in a slew of legislative and personnel changes by the PSD since they took power two years ago that have raised EU and U.S. concern for the rule of law in Romania.

“The PSD continues the assault on justice since coming to power,” the centrist Iohannis told reporters on Thursday.

“Justice is a matter of national interest, and citizens have the sovereign right to decide whether or not to let corruption become state policy,” he said in announcing the referendum.

The PSD has repeatedly said its moves in the judicial sphere are meant to remedy abuses committed by prosecutors and judges.

Romania’s president is empowered to call referendums on issues he or she deems to be of national interest. The May 26 plebiscite would coincide with voting for the European Parliament.

Last month, a European Parliament committee backed Romania’s former anti-corruption chief, Laura Codruta Kovesi, to become the EU’s first fraud prosecutor, despite opposition from the PSD government in Bucharest, which sacked her.

Romania has the EU’s rotating presidency until June 30 but the Kovesi case has further weakened Bucharest’s standing in the bloc, and coincided with an EU push to make funding to member states from its next long-term budget from 2021 conditional in part on their upholding of the rule of law.

Romania’s last referendum was held on Oct. 7 to amend the constitutional wording of marriage to read between “a man and a woman”, rather than the gender-neutral “spouses”. It failed to draw enough voters to validate the result, with only 20 percent casting a ballot against the required 30 percent.