VALLADOLID, Spain  The Macías Picavea primary school hardly looks like the seat of revolution. But this unassuming brick building in a sleepy industrial town has become a battleground in an intensifying war between church and state in Spain.

In an unprecedented decision here, a judge ruled in November that the public school must remove the crucifixes from classroom walls, saying they violated the “nonconfessional” nature of the Spanish state.

Although the Roman Catholic Church was not named in the suit, it criticized the ruling as an “unjust” attack on a historical and cultural symbol  and a sign of the Spanish state’s increasingly militant secularism.

If the judge’s ruling was the latest blow to the Catholic Church’s once mighty grip on Spain, the church’s response showed Spain to be a crucible for the future of church-state relations in Europe.