Three Big Things:
1. To bring a case before any court, one must first establish “standing.” Typically this means proving specific individual harm resulting from the actions of another and demonstrating that the offending party has the power to change whatever’s causing the harm.
2. Being a taxpayer is rarely sufficient to prove standing in the courts to complain about how one’s tax dollars are being used, even if that use is clearly unconstitutional.
3. When it comes to violations of the Establishment Clause, however, unwanted exposure to the offense is often sufficient to show standing in the eyes of the law because, well… Establishment isn’t like anything else.