The case between Mueller v. Allen was a conflict between taxpayers. Now they weren't getting happy to have more money out of their pockets from the state income tax's so that they could pay for Tuition, textbooks, and transportation for kids that go to religious elementary or higher schools, even if their kids didn't go to sectarian or religious schools. The government in Minnesota did, and the question spurred up in their brain which later caused a lawsuit towards the state. Mueller and other Minnesota taxpayers sued Clyde Allen, Jr., the Commissioner of the Department of Revenue in 1983 because an argument was spiked about providing financial assistance to sectarian schools. (Kilman)

The first amendment states "congress shall make no law respecting an establishment of religion (separation) or prohibit free exercise thereof (tolerance). These two are known to be the Establishment Clause and Free Exercise...