The Supreme Court's justices blocked the creation of the nation's first religious charter school on May 22, reigniting ongoing debates about the separation of church and state in the United States. The justices' split 4-4 decision meant a lower court ruling would stand.

Charter supporters and those wary of the eroding separation of church and state heaved a sigh of relief Thursday when an evenly split U.S. Supreme Court blocked the opening of what would have been the...