“Millions of American citizens and Mexicans who live in border communities and pass the border routinely and companies who cross the border routinely would be plunged into a degree of disruption and chaos that is just astonishing,” said Omar Jadwat, the director of the American Civil Liberties Union’s immigrants’ rights project. “Frankly the idea that a president would even float this idea demonstrates how little understanding he actually has of how the border functions.”