Religion is something special in American law. A swelling army of scholars think this is unfair. Kathleen Brady's new book, The Distinctiveness of Religion in American Law, shows how and when equality between religion and nonreligion became the central theme of religion law scholarship, and offers an original and important response that will persuade almost nobody.This relates to the most contentious part of Supreme Court's Establishment Clause jurisprudence. One can argue that America's Founders were concerned about equality and equal treatment/respect in religion that transcended "Christianity." They argued over whether standards like separation, non-cognizance or accommodation were needed to validate such.
I have reviewed the book for a forthcoming issue of the Journal of Religion. A draft is now on SSRN, here.
For instance, George Washington thought we could have a bill that would tax the general public of Virginia to support the Christian denominations generally, but thought that Jews and Muslims (and "otherwise") should be accommodated with some kind of "proper relief."
Equality between religion and non-religion seems a bigger step. Though it could be argued such is necessary to treat atheists and non-monotheists equally.