Trump has declared that he wants to bar all Muslims from entering the USA. That includes US citizens. I'm not sure what his plans are for returning members of the military.
Lots of people are saying "How terrible" and "Sounds like Hitler". But what I'm saying is, "How?"
Let's suppose I decide to spend a couple of days in New York, where they have great food. Latkes (which someone told me is the same as hash browns, but ladysolly told me isn't, and she should know), salt beef (which they call corned beef, whereas in the UK corned beef is something completely different, so beware) and cheesecake (and here's another caveat; in the UK there's two sorts of cheesecake, the sort you get in New York, and another sort which is *completely* different and not very nice). But I'm getting digressed on the subject of food; let's get back to Trump. And let's suppose there's a "no-Muslim" policy in place.
Obviously, they could just ask me, "Are you a Muslim". And I'd say "No". But that's hardly proof, and it's what you'd expect a Bad Person to say. So how can I prove that I'm not a Muslim?
They could offer me a bacon sandwich, but I just love bacon sandwiches, so I'd happily eat it, although a religious jew wouldn't, thus proving ... nothing at all.
They could check for male genital mutilation, which I do have (at eight days old, I was too young to object), but I've read that a lot of Americans have this too.
All of these negative checks, aren't going to work. But what about a positive check? A positive check would be a proof that I was some non-Muslim religion - if I'm Christian or Jewish, I can't be Muslim, right? So how about a proof that I'm something else.
They could ask me for a recital of the Nicene Creed, which non-Christians are unlikely to know, but the problem is, I doubt if many Christians know it either. Nor do I.
They could ask me to recite the Shema, but I'd fail that, unless I was given time to learn it before the exam.
No - I just don't see how they'd do this. The hope is that by keeping out all Muslims, they would keep out nasty extremist terrorists; the difficulty is that a nasty extremist terrorist would pretend not to be a Muslim, and I can't see how you'd be able to tell the difference.
But there is one way.
Don't let *anyone* enter the USA, and if any US citizen leaves, don't let them back in.
That should do it.