Another stupid idea from Trump, Mexico is our second biggest trading partner. It would dramatically increase costs of many goods in the US.
note
"If you are thinking about a total shutdown of the border, then it's hundreds of millions of dollars a day -- maybe a billion," Duncan Wood, director of the Wilson Center's Mexico Institute, told CBS MoneyWatch. "It's an economic impossibility. Literally, the two economies would grind to a halt. Both economies are set up to depend upon cross-border trade."
Experts say the best analogy for closing the border with Mexico may be 9/11. The U.S. didn't seal the entire border after Sept. 11, 2001, instead enacting a "Level 1 Alert." That meant customs officers had to physically search every vehicle before allowing entrance.
The backlogs "had an immediate effect in places like the auto industry," he said. "In a couple of days, GM and Ford were running out of parts they needed for production."
If Mr. Trump did order the closure of the southern border, costs for imported parts and goods would quickly spike, "from TV sets to washing machines to computers to avocados. Just run down the list of stuff that Mexico exports to the U.S.," Alden said.
https://www.cbsnews.com/news/what-president-trumps-threat-to-close-the-u-s-mexico-border-would-cost/
Mexico cannot even do what Trump wants, they cannot stop illegal immigration, They simply do not have the manpower to do it.