Don’t mean to be preaching to the choir, but if there are any uninformed out there:
The First Amendment prohibits Congress from establishing a Federally mandated approved religion for the country. On the other hand, states are free to do so for their state, unless their constitutions prohibit them from doing so. In the early years of America,some states had state sanctioned religions.
The Dope from Hope hits the populist high note again, shedding heat, but not light, on an important topic.
Yes, some states still discriminate against atheists, for example, forbidding them from holding office. Also, though, note that state-sanctioned religion isn't necessarily the same as compulsory religion.
You cannot have a religious test for public office according to the Constitution. That’s beyond “neutrality” ~ it gives candidates for election or appointment the opportunity to be raving mad atheists if they wish.