According to a working paper from the National Bureau of Economic Research, if Trump is successful in removing illegal immigrants from the US the impact to the US economy would be staggering. The paper's conclusion is that illegal/undocumented immigrants, which makes up nearly 5% of the active workforce in America today, will contribute something like $5 trillion-with-a-'T' dollars (or roughly 3% of the GDP) in the value of goods and services provided by these people over the next decade.
Remember that many of these people are doing more-or-less menial jobs that the average American worker wouldn't touch with a ten-foot pole — or expects to get paid $15.00 per hour or more for doing. Add to that the fact that many of the current crop of workers are baby boomers who are reaching the end of their employment careers and will be retiring en masse over the same time period, resulting in a shortage of workers which will in turn drive wages even higher as employers are forced to compete for manpower from a smaller total workforce.
So in simplest terms, it is going to cost the US economy roughly $91,000 for each and every illegal worker it boots out of the country. And this, of course, does not take into account the amount of money spent for the teams who will be investigating these undocumented workers, rounding them up, processing them (and holding them while they are being processed for deportation), and finally walking them to the gate and shutting it behind them ... or the cost of that YUGE fence/wall that is supposed to get built to keep them on the outside looking in.
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