However, 8 U.S. Code § 1182 -- current by an act of 2015 -- holds:
(f) Suspension of entry or imposition of restrictions by PresidentThis is the sort of thing that courts ordinarily sort out, and I suspect the courts will chew on this one for a while. It may well be that the Congress has passed incompatible laws, which means sorting out which one overrules the other. Still, I expect a vigorous Article II defense from the Trump administration, and even the Supreme Court is only co-equal to the Presidency.
Whenever the President finds that the entry of any aliens or of any class of aliens into the United States would be detrimental to the interests of the United States, he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or nonimmigrants, or impose on the entry of aliens any restrictions he may deem to be appropriate.
We may be living with this for a while. Good to see that the green card issue, at least, has been sorted out. General Kelly came down on the matter today, and I doubt Trump will buck one of his Marines.
UPDATE: Looks like Trump's base is in no way shocked by this move, as you'd expect given that he campaigned on this for like nine months. One expects that the Quebec mosque shooting will underline the point of wanting to check immigrants carefully -- at least one shooter was from Morocco, which isn't even on Trump's list.
With that plus the pending SCOTUS nomination, the politics of this may settle down. The courts can then do their work in peace.
UPDATE: The Intercept says that the widespread reports that the shooter was Moroccan are false.
UPDATE: The Quebec police now believe the one shooter acted alone, with what news reports are describing as 'two rifles and an AK-47.' I assume they don't know why that's a strange thing to say. Apparently he is a nationalist, which in Quebec means having an intensely French identity.