Romania‘s presidential candidate Calin Georgesku will challenge a decision to contest a runoff election in May, a decision likely to deepen the constitutional crisis in the European Union and NATO member state, one of his advisers told Reuters today.

Georgesku submitted his candidacy for May’s presidential runoff election on Friday amid doubts he would be allowed to run. Romania’s Supreme Court annulled the election in December, two days before the second round of voting, citing accusations of “Russian meddling” in favor of Georgescu, which Moscow denies.

Yesterday Sunday, Romania’s central electoral authority said it had decided to ban Georgesku from running, saying his candidacy was not acceptable after the Constitutional Court annulled the December election result.

The annulment on December 6 of the presidential election over allegations of Russian meddling has put Romania at the center of a dispute between the administration of U.S. President Donald Trump and European countries over how democratic values should be defined.

Appeals against decisions by Romania’s central electoral authority must be filed within 24 hours.

The Constitutional Court should rule on the appeal by Wednesday.

Analysts say it is unlikely the Constitutional Court will allow Georgesku to run again for president of Romania.

The court set a precedent in October when it blocked the candidacy of another candidate, controversially arguing that her anti-European, pro-Russian views “made her unsuitable for the office” (sic).

If the court upholds the electoral authority’s decision, then the three nationalist parties, which hold 35 percent of seats in parliament and had backed Georgesku’s previous presidential bid, risk not having a candidate in the May elections.

George Simion, the leader of the right-wing Alliance for the Union of Romanians – the second-largest party in the Romanian parliament – said he would have a meeting with Georgesku today.

Asked if he was considering running for office, he told reporters: “We will wait to see what Mr Georgescu has to say. We are not ruling out any option, but we are not speculating.”

Georgescu had come in first in last year’s election, and members of the Trump administration have called his annulment an example of European governments’ crackdown on free speech and political opponents.

Six criminal charges have been brought against Georgesku. He is accused of, among other things, inciting actions against the constitutional order, making false statements regarding his campaign financing and founding a fascist and anti-Semitic organization. He denies the charges and is free on parole.