It dawns on Matthew Yglesias that if border enforcement succeeded in driving up wages for the unskilled, some jobs wouldn't be economical to do anymore. But, he doesn't go far enough:
An early scene in "The Man Who Would Be King" takes place in the office of an English colonial administrator in India. To stay cool, he had a big fan over his head flapped by a servant via a string attached to the sitting servant's toe. That's pretty awesome! If wages weren't so damn high here in America, I could have my own Untouchable toe-fanning servant too, instead of having to use my boring, totally unawesome electric fan. I could impress all my friends. (Well, maybe not the friends I already have, but if I had enough servants, I could assign some of them to get me new friends who would be impressed.)
Think of all the other hundreds of millions of jobs that could be created in America if wages fell to 19th Century Indian levels!
Of course, I couldn't actually afford to pay my toe-fanning flunky the full cost of what it would take for him and his family to live in America, but I believe the externalities of my servant's cost of living should be borne by the public at large, not by me. Thus, my worker's kids should get free schooling, the whole family should get free health care at the emergency room, his tenement should get fire and police protection, he should drive without car insurance, etc. Why shouldn't I cost shift my conveniences on to everybody else?