This article considers the ‘tire scrap’ playground case, Trinity Lutheran Church of Columbia, Inc. v. Comer, decided by the U.S. Supreme Court in the summer of 2017, and its implications for federalism in the United States. In Trinity Lutheran the U.S. Supreme Court held that the state of Missouri violated the Free Exercise Clause of the First Amendment by disqualifying a church-owned school from participating in a programme that provided state funding for updating playgrounds. The case has interesting Free Exercise Clause implications, because the Court emphasized the non-discrimination component of Free Exercise. It also has interesting implications for federalism, because Missouri’s State constitutional provision prohibiting state funding of religion was rooted in an era of anti-Catholic bias. These so-called State constitutional ‘Blaine Amendments’ exist in some form in as many as forty states. Although the Court did not explicitly address whether state Blaine Amendments violate the U.S. Constitution per se due to their history of religious animus, the Court held that this Blaine Amendment as applied here violated the Federal Constitution. This could have significant effects for the wall of separation between religion and the state, and might have especially significant implications for state funding of religion, including the ‘elephant in the room’ in this case, state educational ‘voucher’ programmes that provide state funding to parents who send their children to religiously affiliated schools.