So we will have a massive increase in legal immigration, much of it unskilled, and a significant but modest reduction in illegal immigration compared to what we have been expecting. The economic benefits for people coming here will presumably be substantial; that’s the major reason they’ll come. The economic benefits for people already here will, it seems likely, be negligible. Some people already here, notably low-skilled workers, will for several years see their wages fall as a result of the bill. And we’ll get to have this whole debate again in ten years, when it will be time to bring another large group of illegal immigrants out of the shadows.

It is certainly open to supporters of the bill to dispute the CBO’s pessimistic projection about future illegal immigration. But if they do that, they will have to also throw out the deficit and GNP numbers they’ve been touting, since as I understand it those projections are based on the number of people that are expected to be here.