The Constitution has nothing to do with who does and does not get into this country from a foreign country. We stopped members of the Communist Party from entering the US. Foreigners have no rights under the Constitution, especially when it comes to entry into the US. We can use any criteria we want.
Excellent and true. Imagine Nazis demanding to be let in in 1942, for example.
The whole thing reeks of moronic stupidity and foolishness.
It was obvious from his amplification that he agrees that there is no constitutional impediment to closing the borders, even to Europeans.
See the PDF at this link. Interesting read on the subject:
http://scholarship.law.georgetown.edu/cgi/viewcontent.cgi?article=1302&context=facpub