The Fort Hood massacre changed nothing. The Time Square bombing attempt changed nothing. The presence of so many of the 9/11 hijackers on overstayed visas has changed nothing: there is still no mechanism for confirming that persons who enter on visas depart on time. Why would one expect Boston to change anything.?

The immigration debate has been resisting new information for years, not only in the traumatic and of course rare instances of terrorist acts by immigrants and their children, but even more in labor economics. Much thinking about immigration remains shaped by statistics from 30 and 40 years ago, when immigrants arrived with higher levels of education than natives and equaled native wages within a decade.

We don’t need horrifying acts of violence to prove that the United States is choosing its immigrants unwisely. Until 1970, immigrants to the United States were better educated than natives. Immigrants who arrived before 1970 took a decade or so to adjust, but then earned more than natives.

Since 1970, however, the skill levels of immigrants to the United States has sharply deteriorated.