The Supreme Court heard arguments Wednesday in a pivotal case over whether Oklahoma may establish the nation’s first taxpayer-funded religious charter school — a legal showdown with sweeping implications for the First Amendment’s religion clauses and the future of public education.

The proposed school, St. Isidore of Seville Catholic Virtual School, would offer K-12 instruction infused with Catholic doctrine and operated by the Archdiocese of Oklahoma City and the Diocese of Tulsa. Though never opened due to litigation, if approved, it would be the first religious charter school in the country.