In most instances taxpayers lack legal standing to sue the government merely because they object to how the government is spending tax dollars. Instead, the courts require that someone suffer a direct and personal injury that entitles them to sue. This requirement of legal standing helps prevent the courts from becoming a quasi-legislature where policy arguments are debated rather than a forum to decide specific legal disputes.
The same principle applies in most constitutional cases. If the government violates a constitutional right, like the Eighth Amendment's prohibition on cruel and unusual punishment, the injured individual can sue in court to hold the government accountable for its abuses.
But what happens when the alleged constitutional violation involves the First Amendment's establishment clause that prohibits the government from promoting religion?
"The establishment clause is different. It is designed to limit the government from doing things which tend to favor or help people without necessarily hurting anybody in any obvious material way," Professor Lupu says. "Because of that, the rules about who can sue to complain about alleged violations of the clause are unusually important."
If you follow the normal rules that you have to be injured in some direct way before you can complain about what the government has done, the establishment clause would never get enforced in the courts, Lupu says. "The government would put up crèches and crosses and menorahs and would spend money on religion, and nobody could challenge it because nobody is hurt in obvious ways by those kinds of activities."
Had the courts consistently enforced the rule on standing, establishment-clause cases filed by ordinary Americans would be rare to nonexistent. But in 1968 the Supreme Court carved out an exception that allows taxpayers to file establishment-clause lawsuits challenging congressional spending that benefits religion.