The policy, dubbed by some as "Zach's rules" after a young New Jersey boy whose family fought the restrictions, allows students to express their religious beliefs in homework, artwork and other written and oral assignments, and calls on teachers to judge and grade on academic standards and without discrimination.

"At last, we finally have 'teeth' in the guidelines that supposedly have governed school policies since the Clinton administration," said Seamus Hasson, president of the Washington-based Becket Fund for Religious Liberty.

The "Guidance on Constitutionally Protected Prayer in Public Elementary and Secondary Schools" went into effect in March as part of the No Child Left Behind ...