Separation of Church and State
The First Amendment reads in part, "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof;".
At the time, this was pretty clearly meant that there would be no single Federal Church (like the Church of England), and that the Federal Government would be forbidden from interfering with the States and communities enforcing whatever religion they wanted. What it did not mean is that there would be a clear separation of Church and State or Local Government -- just strictly the Federal Government could not put one religion above the others. The Founding Fathers would have been appalled that anyone would use the 1A to restrict religious practices, in school or anywhere else for that matter. A decade later, Jefferson had wrote the line called "the Separation Clause" in a private letter, but even that didn't mean what progressives later pretended: at the time of the writing, and long after, States had official religions, Prayers were done in Congress and Courts, and no one had problems with prayers in School. In fact, the government's first Holiday was Thanksgiving whose purpose was specifically required "...shall be yearly and perpetually kept holy as a day of thanksgiving to Almighty God."
So you can argue that you WANT the Separation of Church and state, or that a few rulings over the years by the Supreme's help reinforce that. As long as you're not dishonest enough to imply that was the Original Intent, which is most certainly was not.
- Mediocre article by Time that glosses over the important stuff: http://time.com/5103677/church-state-separation-religious-freedom/
- Theologian view: https://www.youtube.com/watch?v=1D3YuEYcAro
- History.com gets it all wrong and misleads their viewers on what it means (it did NOT mean to separate "government" from religion - it was restricting the Federal Government from interfering with State and Local religions. They go on to mislead that this is why prayer is not allowed in schools (something that was readily allowed at the time of the Bill of Rights and for 100 years afterwards, without anyone having a problem with it): https://www.youtube.com/watch?v=RC9uqHtnvzo