The Travel Press is Reporting the ‘Trump Slump,’ a Devastating Drop in Tourism to the United States. At the same time, the Homeland Security chief has reported illegal border crossings dip 40%. Neither of those things are surprising. In East Berlin, after the wall, tourism and illegal immigration dropped. Rhetoric will stop some people from coming to this country, legally or otherwise. Harsh immigration measures will stop some people. A wall will stop some people. The Soviets were able to control their borders pretty well during the cold war. The history of East Germany during the cold war is a history of people trapped by a wall, though even in that case, the wall did not stop emigration entirely. People still escape from North Korea.
The question has never been “is it possible to reduce immigration?” The question is “is it right?”