The Two Clauses and Their Tests

In practice

Start with the text, because the text is the part that has not moved (Gov 104, Gov 105): no established religion, no prohibited exercise. Everything else in this story is method. On the establishment side, Engel showed the clause restraining a state that sponsored prayer (Gov 139), and Lemon gathered the case law into three prongs — secular purpose, no advancing or inhibiting, no excessive entanglement (Gov 140). Those prongs governed for decades, and then in 2022 Kennedy stated the Court had abandoned them along with the endorsement test, reading the clause instead by historical practices and understandings (Gov 141). The clause did not change; the method did, which is why a study guide printed before 2022 can be accurate about the words and wrong about the law. Now the exercise side. Sherbert demanded a compelling interest and narrow tailoring (Gov 143), and Yoder applied it to compulsory schooling (Gov 144). Smith then held that a neutral, generally applicable law needs no exemption at all (Gov 145), Congress answered with a statute restoring the older standard (Gov 147), and Boerne confined that statute's reach (Gov 148). Read the two sides together and the shape is the same on each: a clause that stays put, and a test that moves.