[silverleaf]

so the principle is, the president of the US can unilaterally order sanctions against the citizens and assets of a foreign nation... just not “big” sanctions

[kabar]

It is not a principle, but the law. We have laws that determine who can be issued a visa to enter this country. The President is just implementing them--in this case. He doesn't need to go to Congress.

Citizens of other countries do not have a right to enter the US any more than we have a right to enter theirs.