Same kind of thinking that led to the Asian Exclusion Act in the 19th Century and the National Origins Act of 1924. Both were a blight on the body politic upon passage. That kind of thinking is national self sabotage.
The Trump administration and Stephen Miller in particular have been openly peddling rhetoric that portrays “Third World” immigrants and their descendants—as many as a third of the U.S. population—as perpetual and unwelcome foreigners.