From the article:
One of the most interesting studies came from Michael Clemens of the Center for Global Development. He found that when Mexican braceros — farm workers brought in to work for a defined period of time — were suddenly expelled from the U.S. in the 1960s in an effort to raise wages for U.S. farm workers, nothing of the sort happened. Instead, farm owners invested in technology to do the work with fewer people. Wages stayed as low as ever.
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