America has a choice to make before the choice is made for us. We can decide now that the Constitution is the final authority in this country — or we can wait until competing systems of authority become so deeply established that reclaiming that principle becomes far more difficult.This isn't hypothetical. It is already a subject of congressional hearings, state investigations and public debate.In February, a House Judiciary Subcommittee examined the relationship between political Islam, Sharia law, and the Constitution. A second hearing followed in May, with lawmakers considering safeguards to ensure that American courts cannot enforce religious or foreign-law...