Boss
Take a Memo:
If Trump had issued an EO that said we're not accepting anymore immigrants from these Muslim countries.. that would not be Constitutional. The President can't make immigration policy. Congress could do that, just as they passed the Immigration and Nationality Act of 1965. But what Trump did was put a temporary hold on travel from certain countries until we can get a verifiable vetting process in place.
Are you sure about that? I thought it was in the President's power to set the numbers of immigrants coming in from wherever, that's how we ended up with Obama agreeing to take tens of thousands "more" refugees, and Clinton campaigned with the same promise.
I think that is due to the classification as "refugees" which are exempted from the provisions of the INA for humanitarian reasons. According to the Constitution, Congress is the authority in charge of immigration and naturalization.