(Reuters) - Romania's constitutional court rejected on Wednesday a law to change the electoral system, dealing a further blow to a government that has been rocked by a string of misfortunes in the last week.
The governing leftist Social Liberal Union (USL) had passed the change to first-past-the-post voting, which would have been used in a November parliamentary election, replacing the current mixed majority and proportional system.
"The Constitutional Court established, with a unanimous vote that...the law...is unconstitutional," it said in a statement.
Analysts said the USL, whose leader Prime Minister Victor Ponta is under pressure over plagiarism charges, would have benefited from the change because of its strength in individual constituencies.
It performed strongly in local elections earlier this month and may win a majority anyway, but the electoral law change could have given Ponta even stronger control over parliament.
The opposition Democrat-Liberal Party (PDL) had challenged the law, saying it went against the sovereignty of the people. The court did not give full reasons for its judgment.
Former Prime Minister Adrian Nastase, still an important figure in the USL, was taken to jail this week to start a two-year sentence on a corruption charge, which was delayed when he attempted suicide.
Ponta has also been embroiled in an unseemly argument with his political opponent, President Traian Basescu, over who will represent Romania at a Council of Europe meeting this week.
The constitutional court also ruled the president should attend as he is head of state, but Ponta said he would travel to Brussels anyway.
(Reporting by Sam Cage, editing by Diana Abdallah)