Dani Rodrik has a very useful post laying out his arguments with economist George Borjas on guest worker programs. Particularly important is his point on how settled the facts of the matter tend to be: " Our best point estimate has to be that guest workers will create a small net gain for the U.S. economy, with a large margin of uncertainty on both sides. They would also likely exert downward pressure on U.S. wages, especially in the short run. On the other hand, the gains to guest workers themselves is quite large. If you are in gross disagreement with any of these points, do not look to either one of us for support for your position."
Rodrik continues: "But, and here is where we begin to disagree, I do not find putting zero weight on foreigners to be an acceptable moral position. I am willing to accept--and in fact would advocate--a weighting scheme that overweights our own citizens relative to other countries'. But a weight of zero is surely unacceptable. This has bite precisely because the gains to foreign workers are so huge--given the big differences in labor productivity in sending countries. Given these large differences, you would have to put if not zero, a near-zero weight on foreigners to still think that a guest worker program is a lousy idea."
That's not quite true. There are a variety of political reasons you could think guest workers are a bad idea, including a concern over populating the country with a class of workers who are completely disenfranchised and temporary. The larger that class becomes, the more political problems one could imagine occurring. But so far as the economic argument goes, Rodrik's point is sound. Indeed, the economics blogger NotSneaky cleverly mathed it up here.
