Romania's president cannot block the government's attempts to dismiss the country's chief anti-corruption prosecutor unless they are illegal, the Constitutional Court ruled.
The decision opens the way for the removal of Laura Kovesi, who has taken on politicians from local mayors to government ministers accused of illicitly profiting from their positions.
The government has repeatedly tried to undermine the powers of Kovesi's anti-corruption prosecutor's office (DNA) which it accuses of running a politicised campaign.
Attempts to change the law to reduce sanctions on corruption offences prompted thousands of protestors to take to the streets at the beginning of the year.
However, when justice minister Tudorel Toader called for Kovesi's removal, she was reprieved by president Klaus Iohannis.
The government took the question to court and yesterday won a victory limiting the president's powers in the matter to assessing the legality of the action.
An estimated 2,000 people gathered outside the headquarters of the ruling social democrats after the decision, chanting "Dictators" and "Rats."
The European Union, which has monitored Romania's anti-corruption efforts closely, has praised the work of the DNA while the Council of Europe's anti-corruption watchdog warned last month that recent government initiatives were threatening the rule of law in Romania.
Last November, Kovesi told Euronews that her office had been subject to "inbelievable attacks" aimed at limiting its ability to carry out investigations.