In Diffenderfer et al. v. Central Baptist Church of Miami, Florida, Inc., et al., 1971, the U.S Supreme Court was asked to decide on a case concerning the separation of church and state as stipulated in the First Amendment. The plaintiffs challenged a Florida law that exempted property used for religious purposes from taxation if it was also used regularly for secular purposes such as public meetings or entertainment events. They argued this violated their constitutional rights by indirectly supporting religion with tax benefits. However, while the case was pending before the court, Florida's legislature repealed this exemption law and replaced it with one that only exempted properties exclusively used for religious services or instruction from taxes. As a result of these changes in legislation during litigation process, Supreme Court dismissed appeal as moot because there were no longer any live issues to be resolved.

In the dissenting opinion for Diffenderfer et al. v. Central Baptist Church of Miami, Florida, Inc., Justice William O. Douglas argued that the case should not have been dismissed as moot because there was a substantial question about whether or not religious activities were being conducted on property that had been acquired through eminent domain for public use - specifically, a parking lot owned by Central Baptist Church in Miami. He pointed out that if such activities were taking place and they violated the Establishment Clause of the First Amendment (which prohibits government establishment of religion), then it would be appropriate to grant an injunction against them even though no tax exemption was currently being claimed for this particular piece of land.