Engel v. Vitale
The State of New York made a voluntary prayer to say at the start of each day. The prayer said "Almighty God, we acknowledge our dependence upon Thee, and beg Thy blessings upon us, our teachers, and our country."
The Court ruled 6 votes for Engel, 0 votes against. Even though the prayer was nondemional and voluntary it still doesn't save it from being unconstitutional. The decision today is still not liked by majority of Americans