The case, a major test of the separation of church and state, was an unexpected loss for religious rights advocates after a string of victories.

Attorney General Gentner Drummond, also a Republican, sued to stop the school. He called the 4-4 vote “a resounding victory for religious liberty” that also will ensure that “Oklahoma taxpayers will not be forced to fund radical Islamic schools, while protecting the religious rights of families to choose any school they wish for their children.”

A divided 4-4 high court let stand an Oklahoma Supreme Court ruling prohibiting the first religious public charter school in the U.S. Justice Amy Coney Barrett recused herself.