The article "How L.A. kept out a million migrants" informs us that a million or so illegal aliens who would have come to Los Angeles actually went elsewhere.

This is not because we took the straightforward tack of enforcing our immigration laws. Rather, it's because of:

* too few low-wage jobs, word of which made it back to sending countries (who knew?), resulting in fewer coming.
* the minimum wage rose, driving low-wage employers into other states. * while our immigration laws weren't enforced (the horror!), our industrial laws were enforced, resulting in sweatshops shutting down.
* attempts to shut down tenement buildings
* lack of affordable housing due to NIMBYs

Now, think of where we'd be if in addition to the above we'd also helped enforce our immigration laws rather than serving as a sanctuary city.