In another bombshell opinion, the US Supreme Court’s conservative majority has upended the way it understands and applies the clause of the constitution that prohibits the establishment of religion. Completing the revolution begun in last week’s decisions expanding gun rights and overturning abortion law, the court said in Kennedy v Bremerton School District that it was abandoning long-established constitutional doctrine and replacing it with a historical analysis.

This means that in establishment cases the court will no longer examine government action to see if it has a secular purpose and effect, or sends a message of government endorsement of religion. Instead, the court will consider whether government action violates the establishment clause only “by reference to historical practices and understandings”.

The court’s 6-3 decision represents a once-in-50-years change in the law of church and state. The court used the case of a high school football coach, disciplined for praying at the 50-yard line immediately after games, to overturn two long-established doctrines...