I went to look for myself that the law says about the President being allowed to ban certain people from immigrating to the US. The clause is in U.S. Code Title 8, Chapter 12, Subchapter II, Part II, § 1182. Here is a link to where I found this statute:
Scrolling down, very far down in this text you will see this clause:
(f) Suspension of entry or imposition of restrictions by President
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. Whenever the Attorney General finds that a commercial airline has failed to comply with regulations of the Attorney General relating to requirements of airlines for the detection of fraudulent documents used by passengers traveling to the United States (including the training of personnel in such detection), the Attorney General may suspend the entry of some or all aliens transported to the United States by such airline.
That’s it folks. Says the President can do what Trump has done for as long as he wants to. Jimmy Carter did it, Bill Clinton did it, and the darling of the left, Barack Obama did it. But for some reason the Left has decided that President Trump can’t do it.