Romania's Constitutional Court on Monday validated the shock first-round result in its presidential election, setting the stage for a run-off vote on Dec. 8 that could upend the country's pro-Western orientation and erode backing for Ukraine.

Romanians cast ballots Sunday in a parliamentary election sandwiched between a two-round presidential race, the first of which has plunged the European Union and NATO member into unprecedented turmoil following allegations of electoral violations and Russian interference.