Donald Trump has recently said, in a variety of forums and using a a variety of verbal saltados, that people who believe in Allah, the Muslim version of God, should not be allowed to enter the U.S. He has apparently slathered onto this steaming dish the claim that even American citizens who travel abroad in Muslim countries should not be readmitted.

One could argue, as Justin Wolfers has done in the NYTimes, that we shouldn’t focus so much on the “noise,” but rather recognize the signal.  Maybe, but words have meaning, and arguments have consequences.  Could any reasonable person take Trump seriously?  Is there an argument here other than simple religious bigotry?

I recently encountered (or reread, but noticed for the first time, perhaps because of recent events) a portion of Locke’s Letter Concerning Toleration.  Here is the relevant passage (emphasis added) :

[T]he magistrate ought not to forbid the preaching or professing of any speculative opinions in any Church because they have no manner of relation to the civil rights of the subjects. If a Roman Catholic believe that to be really the body of Christ which another man calls bread, he does no injury thereby to his neighbour. If a Jew do not believe the New Testament to be the Word of God, he does not thereby alter anything in men’s civil rights. If a heathen doubt of both Testaments, he is not therefore to be punished as a pernicious citizen. The power of the magistrate and the estates of the people may be equally secure whether any man believe these things or no. I readily grant that these opinions are false and absurd. But the business of laws is not to provide for the truth of opinions, but for the safety and security of the commonwealth and of every particular man’s goods and person. And so it ought to be. For the truth certainly would do well enough if she were once left to shift for herself. She seldom has received and, I fear, never will receive much assistance from the power of great men, to whom she is but rarely known and more rarely welcome. She is not taught by laws, nor has she any need of force to procure her entrance into the minds of men. Errors, indeed, prevail by the assistance of foreign and borrowed succours.

Later, Locke elaborates (and again emphasis added):

That Church can have no right to be tolerated by the magistrate which is constituted upon such a bottom that all those who enter into it do thereby ipso facto deliver themselves up to the protection and service of another prince. For by this means the magistrate would give way to the settling of a foreign jurisdiction in his own country and suffer his own people to be listed, as it were, for soldiers against his own Government. Nor does the frivolous and fallacious distinction between the Court and the Church afford any remedy to this inconvenience; especially when both the one and the other are equally subject to the absolute authority of the same person, who has not only power to persuade the members of his Church to whatsoever he lists, either as purely religious, or in order thereunto, but can also enjoin it them on pain of eternal fire. It is ridiculous for any one to profess himself to be a Mahometan only in his religion, but in everything else a faithful subject to a Christian magistrate, whilst at the same time he acknowledges himself bound to yield blind obedience to the Mufti of Constantinople, who himself is entirely obedient to the Ottoman Emperor and frames the feigned oracles of that religion according to his pleasure. But this Mahometan living amongst Christians would yet more apparently renounce their government if he acknowledged the same person to be head of his Church who is the supreme magistrate in the state.

Now, Locke is taking a shot at Catholics here, with the “Mufti” playing the role of the Pope in Rome.  To be clear, Locke thought that openly Catholic citizens were in fact a problem.  Not because of the religious doctrine they held, though he thought that doctrine to be absurd.  The problem was that a consequence of honest faith in Catholicism meant that one rejected the law, and sovereignty, of the civil authorities in England in favor of a civil, not just religious but civil, authority in Rome.  This point has been noted elsewhere, and on it I will say no more.

The relevant question for present purposes is whether one can, and perhaps should, understand Trump’s point in the same context.  That is, the claim is not that religious freedom should be limited.  Rather, Trump’s claim is the same as Locke’s:  any religion that ipso facto requires loyalty to a foreign power,  or requires that an honest believer reject the civil authority and its laws, is a political threat and an overt incitement to violence and revolution.  Locke’s experience was that Catholic and Protestant could not coexist peacefully.  Is there anything in American experience that could say that US government and laws cannot coexist with domestic radical Islam?

My own view is that Trump has this wrong.  But I’m not as sure that Trump has this wrong as I was before I reread Locke.