The first amendment to the Constitution protects religious freedom and prohibits establishing a national religion.
But in order to have those freedoms and prohibitions actually exist, it requires that the final authority in the matters of religion be secular and free from religious influence. In order to have government protect religious freedom, government must have the same freedom from religious influence. These two freedoms are two sides of the same coin. Freedom of religion requires freedom from religion.
Take for example the current controversy surrounding a proposal to build a Muslim mosque near the site of the September 11, 2001 massacre of more than 3,000 people in New York City. This massacre was committed by Muslims. In many parts of the world Muslims celebrated the massacre. Not surprisingly therefore, many US citizens are offended by this particular proposal.
While the Constitution clearly gives Muslims a right to practice their religion freely, it also clearly requires a secular process of approving the church project. The desire to build the church comes in the form of a request that must be approved by a secular body. It cannot be a demand, it must be a request.
Thus, the secular process is required and sacrosanct. Whether the final approval or disapproval of this particular church building proposal comes in New York City or before the US Supreme Court, the final authority resides in a secular process. Not in a religious one.
This doesn’t make the decision any easier. But one thing is Constitutionally clear, the decision will be made in a secular arena free from religious influence.