The coalition’s candidate, Crin Antonescu, was third in Sunday’s first round, far behind top finisher hard-right nationalist George Simion and pro-Western reformist Bucharest Mayor Nicusor Dan.
“Rather than let the future president replace me, I decided to resign myself,” the prime minister told reporters after a meeting at the headquarters of his Social Democratic Party, or PSD.
Sunday’s rerun underscored strong anti-establishment sentiment among Romanians and signaled a power shift away from traditional mainstream parties.
It also renewed the political turmoil that has gripped the European Union and Nato member country.
The rerun took place months after a top court annulled the previous race following allegations of electoral violations.
The unprecedented decision plunged Romania into its worst political crisis in decades.
The prime minister had said one aim of forming the coalition last December – after the failed election – was to field a common candidate to win the presidency.
After Sunday’s vote, he said, the coalition now “lacks any credibility.” It is made up of the leftist PSD, the centre-right National Liberal Party, the small ethnic Hungarian UDMR party and national minorities.
Ciolacu said his party would not officially support either candidate in the final presidential vote on May 18. “Every PSD supporter will vote as they wish, according to their own conscience,” he said.
An interim prime minister will be selected from the current Cabinet of ministers and appointed by interim President Ilie Bolojan, who noted Ciolacu’s resignation and is expected to make an appointment on Tuesday. (AP)