The Supreme Court stepped into one of the most contested fronts of the US culture war on Monday, ruling that the display of framed copies of the Ten Commandments in Kentucky courthouses crossed the constitutional line between church and state.

The five-to-four decision provoked an angry response from Justice Antonin Scalia, who took the unusual step of reading his dissenting opinion from the bench. “Today's opinion ratchets up this court's hostility to religion,” he said, his voice emotional.