Haven't you seen the mass amount of video and reporting about people waltzing across and claiming asylum. Many overstay their visas, true. But many just come across. If you cut the illegal immigration by 1/3 the cost of the wall would be paid off in less than 2.5 years. However the wall would stay up giving it an insanely net positive ROI. FAIR puts the cost of illegal aliens at 100 billion per year, which is a low estimate. CNN claims Trump's wall will cost 25 billion, which is a high estimate - and a one time cost. USA already takes in more legal immigrants than any other country. With better border control we could grow that number and help more people as well as keeping our country and citizens safe. Illegal aliens cross with coyotes, you get human trafficking and drug trafficking. Violence and cartel activity. It's clear and simple logic.