[morsch]

Ok, so there's two things one can read from this: 1) It's okay to prevent (alien) muslims (henceforth A) from entering the country because it was okay to prevent Iranians from entering (B). 2) It's legal for the president to do A because it was legal to do B.

Proposition 1 is obviously false: whether or not it was okay to prevent one group (based, in B, on nationality) from entering simply has, in the general case, no bearing on whether or not it is okay to prevent an entirely different group (based, in A, on religion). Even if the two groups were closely related, it wouldn't mean much, but this is out of scope since they aren't closely related. On a sidenote, Carter allowed for entry for "compelling and proven humanitarian reasons".

Proposition 2 I cannot judge since IANAL -- and I'd hope the president can't just make up completely arbitrary rules --, but if true, makes the whole debate even more ominous: it's not just an empty threat.

The two propositions are, again obviously, unrelated; the set of legal actions is much larger than the set of sensible actions, for everyone of us but particularly a person with power.