The Supreme Court in Spain on Tuesday approved the government’s plan to exhume Francisco Franco, the former dictator, in a case that revived the debate over his legacy, 80 years after he won the country’s civil war and started building the underground basilica in which he was later buried.

The decision follows a yearlong judicial battle between the caretaker Socialist government of Prime Minister Pedro Sánchez and the family of Franco, who sought to block the exhumation.

Mr. Sánchez, writing on Twitter, called the ruling “a great victory of Spanish democracy,” saying that the exhumation plan had been driven by “the determination to compensate for the suffering of the victims” of Franco.

Franco’s relatives said on Tuesday that they would appeal to the Spanish Constitutional Court, but they will first have to demonstrate that the Supreme Court ruling breached fundamental rights guaranteed by the Constitution.