Religious freedom
I read To an Unknown God: Religious Freedom on Trial, by Garrett Epps. It's the story of Employment Division v. Smith, the case about whether Native Americans had a legal right under the First Amendment to use peyote in religious ceremonies. The Supreme Court's answer was "no"; I think the issue is remarkably subtle and important, and it brings into focus or digs up a lot of other interesting topics.
Epps doesn't talk in much detail about the history of the Religious Freedom Restoration Act, which was passed (and overturned) after Smith was decided. He gives it a few pages but barely mentions why the Supreme Court decided to throw it out in City of Boerne v. Flores (the famous "art gallery owned by an atheist" argument).
I think somebody should open an art gallery called Art Gallery Owned By An Atheist, but I don't think many people would get the joke.
I was particularly interested in RFRA because it was used as a basis for the only recent successful court challenge to the California loyalty oath, in Bessard v. California Community Colleges. But Bessard was almost immediately overruled by City of Boerne. As I've written elsewhere, I had mixed feelings about this, because I thought that Smith and Boerne were correctly decided, but I thought that the laws to which religious objections were asserted in Smith (drug prohibition), Bessard (loyalty oath for public employees), and Boerne (zoning ordinance) were all unjust!
Bessard actually came close to eliminating the loyalty oath entirely, because under other precedents, someone who claimed a religious objection would likely not have been required to provide much more detail. On the other hand, we have United States v. Seeger (where the Supreme Court said that atheists could be conscientious objectors to the draft) -- so the logic of Bessard together with Seeger could almost have created a plausible argument that nobody could be forced to sign the oath!
Except...
Except that that's a complete end-run around the purpose of the RFRA, which was to create special privileges or exemptions based on religious beliefs and not simply based on sincere beliefs. And because the RFRA (under which Bessard was decided) really did set out to create that special status for religious beliefs, it was invalided by the Supreme Court.
(I think I'm overstating what Seeger held too -- it's a long time since I read that opinion, and when I glance at it, it looks much narrower than I'm making it out to be.)