The U.S. Supreme Court ruled in favor of parents seeking to opt their children out of public school instruction that conflicts with sincerely held religious beliefs.

The latest decision is a major legal win for religious interests at the conservative high court, and blurs the line that once clearly separated secular education from religious beliefs.

The decision reverses lower-court rulings that had favored the Montgomery County Public Schools, located in the Washington, D.C. suburbs, and marks a significant victory for religious rights advocates.