“The concept of a ‘wall’ of separation between church and state is a … figure of speech. … The Constitution does not require complete separation of church and state; it affirmatively mandates accommodation, not merely tolerance, of all religions, and forbids hostility toward any. Anything less would require the ‘callous indifference’ that was never intended by the Establishment Clause. … Indeed, we have observed, such hostility would bring us into ‘war with our national tradition as embodied in the First Amendment’s guaranty of the free exercise of religion.” – Chief Justice Warren E. Burger, cited in Zorach v. Clauson