Discrimination Between Religions: Some Thoughts on Reading Greenawalt's "Religion and the Constitution: Establishment and Fairness"

Suppose the core teachings of a religion with a significant number of followers inside and outside the United States entail that significant parts of the United States Constitution, including the free exercise and establishment clauses of the First Amendment, ought to be replaced either by peaceful processes such as voting or, if need be, by threats and use of force, and that governance of the United States, or of such regions, big or small, as can be brought under the religion's sway, ought to be entrusted to its followers. Would it be constitutional for Congress to forbid the entry to the United States of members of that religion unwilling to make a public declaration renouncing that teaching? Should it be? I raise these questions as a kind of test of the thesis prominent in Kent Greenawalt's fine book, that both of the religion clauses "forbid discrimination among religions" (p. 13) (emphasis in original), and that "[ o ]ne of the most powerful principles of the religion clauses is that the government may not favor some religions at the expense of others" (p. 212). You may say: Please, let's just stay in the real world. And spare us the embarrassment of trolling through other people's