It’s the Establishment, Man

Today’s question: If a government action does not pass the secular “Lemon test”, it is unconstitutional under what 1st Amendment clause?

The answer: Establishment Clause
Under the “Lemon” test, government can assist religion only if (1) the primary purpose of the assistance is secular, (2) the assistance must neither promote nor inhibit religion, and (3) there is no excessive entanglement between church and state.