As far as I know the US is not officially in war with any of these countries. And what about Muslim citizens of other countries?
Besides, who do you think is not registered yet? If you apply for a visa to the US, you get scrutinized, biometrically photographed, fingerprintef and registered. And I can tell you from my experience that if you apply for a work permit visa, you get therally interogated and have to submit a full CV, and from that moment on, it looks like the US immigration authorities know everything about you. So imagine what happens to people who apply for citizenship. The only thing this new registration could mean is that the information will become open to the public. And that's discrimination, which you can expect to have all kinds of implementations that has nothing to do with national security.
RE: "Donald Trump supporter defends stance on potential Muslim registry", Megyn Kelly show