One caveat: Eberstadt is off-track about the effect of immigration. He challenges the idea that the failure to reduce the percentage of Americans below the poverty line is due to the influx of illegal immigrants. That's a straw man: the argument is that many immigrants--illegal or legal--tend to start with lower wages, then move into higher brackets over time.
It's not illegals, per se. Rather, as Arnold Kling says:
My metaphor for income distribution is an escalator, with new families and immigrants starting at the bottom and most people moving up.The current recession won't change that fact--just ask the 800,000 Vietnamese boat people who arrived during the woeful Carter years.