A U.S. Supreme Court decision ruling that state laws authorizing partial payments of teachers' salaries at private schools—all or most of which were sectarian schools—fostered excessive entanglement between church and state and violated the First Amendment establishment clause.
Drawing from its previous establishment clause cases, Lemon formulated what's often referred to as the "Lemon test," a three-factor inquiry used to decide whether laws and policies pass establishment clause muster. Under this test, a challenged law or policy:
Lemon v. Kurtzman, 403 U.S. 612-13 (1971) (citations omitted).
Though it hasn't been formally overruled, in Kennedy v. Bremerton School Dist., 597 U.S. ___ (2022), the Court argued that Lemon has been "abandoned" in favor of an approach that relies on "historical practices and understandings." Id. at ___.