The Supreme Court’s conservative majority on Wednesday seemed open to backing the creation of a Catholic charter school in Oklahoma, a decision that would expand the availability of taxpayer money for religious education in school systems across the nation.

The U.S. Supreme Court grappled with whether charter schools are public schools and whether the Constitution permits a religious charter.

The case tests whether public money can be used to fund a religious charter school in Oklahoma, and its outcome could affect how public education funds are used in virtually all states.