First they came …
The U.S. government has quietly created a second-class federal prison system specifically for immigrants. For years the Department of Homeland Security has been known as the agency that houses immigrants awaiting deportation. However, tens of thousands of additional immigrants, most serving sentences for immigration crimes, are held by the Bureau of Prisons each night before being sent back.
And it’s all part of a lucrative business model which has funneled billions of taxpayer dollars into the private prison industry.
I wonder… is the for profit prison industry depending on immigrants to replace the lost revenue of prisoners incarcerated for drug offenses should (as seems likely), the “war on drugs” continue to be de-escalated? And… if — as right wingers and other reality-challenged people wish — immigrants were not crossing the border, would the private prison industry find some other group to fill their quotas?
The Mex Files 
They would change their focus in a flash.
Ask yourself what happened to the Prohibition units of the US Federal government?