Mueller v. Allen

Minnesota's tax law let all taxpayers deduct actual tuition, textbook, and transportation expenses for dependents in elementary and secondary school, applying equally to parents of public and nonpublic school children, though nearly all nonpublic school students in practice attended religious schools. Mueller (plaintiff) sued Allen (defendant) in federal court, arguing the deduction violated the Establishment Clause; the court of appeals upheld the law, and the Supreme Court granted certiorari.