MADRID — Four decades after Spain transitioned from Franco’s dictatorship to democracy, the country’s far right has found its voice again in the nationalist, anti-immigrant Vox party.

The group made its mark in December in regional elections in Andalusia, in southern Spain, where it won parliamentary seats for the first time.

In the greater political sphere in Spain, Vox remains a small player. But some analysts say its appeal could spread, making it an important wild card in European Union parliamentary elections in May, when more traditional parties will be trying to hold off nationalist parties on the Continent.