Constitutional Law II
If a law would violate the Free Exercise Clause, then an accommodation must be made for religion.
Even where the Free Exercise Clause is not violated, the state may accommodate a religious practice, unless granting such a protection to religious people would violate the Establishment Clause (Lemon test). However, it does not have to accommodate.
The state has some play-in-the-joints where neither the Free Exercise Clause nor the Establishment Clause are violated, and it can thus choose to accommodate religion or to not.
If a tax accommodation is made to religious organizations, it must also be made to secular organizations.