I have argued numerous times, in numerous places, that the most effective approach to immigration is to let the marketplace, rather than government bureaucrats/central planners set arbitrary quotas. For years we had low unemployment and significant illegal immigration because the marketplace -- in a somewhat bubblicious manner in retrospect, to be sure -- was able to absorb the work of millions of immigrants when native-born Americans were at close to full employment. Now the bubble has burst and the recession is upon us, and sure enough, immigration has dried up -- the most recent figures in the studies cited in this Register editorial are from 2008 and some 2007, and you can be pretty sure more recent stats will show more decline. Get the bureaucrats out of the way and let the martkethandle things it can handle so much better.
An interesting irony the editorial notes. Fewer Mexicans than might have been expected have returned to Mexico; many seem to have chosen to ride out the recession in this country. The drug-law-related violence down south is part of the reason, but a significant reason is beefed-up border enforcement that makes crossing th bordere more inconvenient and expensive than it used to be. Bet that makes immigrant-bashers happy!