From the article:
At the White House press briefing, Miller cited research by Borjas that supposedly debunked Card’s findings. But that research itself has been debunked. Borjas only found effects on the wages of high school dropouts — and that finding, as the Center for Global Development’s Michael Clemens found, was spurious. A bunch of low-paid workers happened to move into Miami at the time of the boatlift, and Borjas mistakenly interpreted that as the boatlift lowering the wages of people already there. “The data simply does not allow us to conclude that those Cubans caused a fall in Miami wages, even for low-skill workers,” Clemens concluded.
And those immigrants who were let in gained a lot. Clemens and fellow economists Claudio Montenegro and Lant Pritchett have estimated that moving from the Dominican Republic to the US can lead to a doubling of income; from Mexico, wages increase about 250 percent. The effects on the Marielitos were likely of that magnitude. Thousands and thousands of people were made dramatically better off — and few, if any, were made poorer.
Letting people come does a lot of good. But letting fewer in, or kicking them out, really doesn’t. Clemens, Ethan Lewis, and Hannah Postel recently studied the Bracero program, a guest worker visa lasting from 1942 to 1964 that allowed Mexican workers to travel and hold jobs on US farms. When the program was canceled, there was a sudden drop in the immigrant worker population in the US. Clemens, Lewis, and Postel wanted to see if that led, in turn, to an increase in wages for native workers.
It did not. Employers didn’t respond to a dearth of immigrants by increasing native wages; instead, they adopted more labor-saving technology and changed what crops they grew. “The starkest example is California tomato picking, where the excluded braceros were mostly replaced by mass-adoption of mechanized harvesters within just one year,” Clemens explains. “In crops where technologies didn’t exist for quick mechanization — like asparagus and fresh strawberries — exclusion of bracero caused sharp declines in production.”
Kick out the immigrants and you don’t get higher wages. You just get fewer strawberries, and poorer Mexican people with fewer opportunities.