The U.S. Supreme Court has struggled for decades in deciding when government support for prayers goes too far. The justices’ struggle continued Wednesday in a case involving prayers before meetings of a New York town board.

The high court heard arguments in Town of Greece v. Galloway, in which the five-member town board is defending its practice of opening its monthly sessions with a prayer by local clergy. A three-judge panel of the U.S. Court of Appeals for the Second Circuit held that the prayers—overwhelmingly Christian in nature for nearly a decade—gave the appearance of government endorsing religion in violation of the First Amendment’s establishment clause.