It’s hard to imagine in today’s world of completely imaginary immigration crises, but there was actually a time when there was a non-imaginary illegal immigration crisis of sorts in the US. Before Reagan tightened up immigration laws, we had something more akin to migrant labor. People would come across the border, work for a season, and go home. But then crossing the border became a non-trivial endeavor, and migrant workers who were in the country decided it was less risky to live in the US year-round than to cross the border every year. So, under Reagan, the ebb and flow of undocumented workers turned into a more static environment, where once you got across, you stayed.

And this, more than anything, led to your Trumpite boogeymen of “anchor babies” and “chain migration”. Reagan. And of course illegal immigration has declined quite a bit since, and pretty much effectively stopped ten years ago before Obama even took office, so those boogeymen are more of a racist dog whistle than fact these days anyway.