Alvaro Vargas Llosa, at the Beacon, blogs on falling immigration rates during crisis years and border enforcement. His main point is to deny border enforcement policy any credit for this phenomenon, instead allocating it to “supply and demand.” I am not sure if Llosa is responding to some type of increase in frequency of commentary dealing with this topic, but academically I think few scholars attribute much success to border enforcement — in fact, U.S. immigration policy is known to be notoriously bad. The crisis years evidence, for me, shows something different, although a bit more academic (and, I use “academic” loosely, since my experience with immigration theory is relatively short compared to the experts that have supplied me with any knowledge I might have): the “Neoclassical” model of immigration holds more weight than some people like to admit.
The “economistic”, or “Neoclassical,” model of immigration is basically a supply and demand one: immigrants are essentially arbitrageurs, taking advantage of wage discrepancies between countries. This model has been lambasted for being simplistic and unable to explain the actual causes of migration. It has been supplemented by a wide variety of alternatives: structural, linkages, networking , market segmentation and bifurcation, et cetera. All these are more complicated, more in-depth theories that provide more specific causality to migration. For instance, a Mexican might decide to immigrate because he has been displace from his agricultural employment by increased mechanization (structural) and he has family in the United States (linkages). To show the advantages of these models imagine an obvious point of contention for the Neoclassical model: why do Mexicans immigrate to the United States in high volumes, but not Kenyans? Or, why did the rate of immigration from Southeast Asian into the states suddenly rise after the 1950s?
The proponents of these theories, though, tend to be highly protective of their academic fiefdoms. What occurs is outright rejection of rival models and theories, and the adoption of uni-causal reasoning that is insufficient to explain the wide-range of possible reasons that an individual might choose to migrate from one place to another. For instance, most of the literature that I have been exposed to has rejected the Neoclassical model.
What the recent crisis shows is that while a single explanation might be inadequate, this inadequacy does not suggest irrelevance. The Neoclassical model is quite applicable: a fall in incomes has led to a fall in the availability of jobs for Mexican immigrants, in turn causing immigration rates to fall. Of course, the labor market is not one homogenous blob of employment opportunities, and so the Neoclassical theory has to be complimented with more advanced ideas: labor market bifurcation, segmentation, et cetera. In fact, while it may be that in general Mexican labor has much lesser demand, certain industries (or sectors) have maintained their demand or even increased it. Also, the Neoclassical theory does not explain why Mexicans emigrate back to their home countries, but many Asians do not. What does explain it is something akin to the linkages or networking theories, or even a model that incorporates the costs of migration (related to distance, for example). Nevertheless, wage discrepancies and the availability of employment is still an important causal factor behind migration movements.
More than the failure of border enforcement and immigration policy, what the recent crisis suggests to me is a failure of the academic community to put forward a synthesize and comprehensive theory of theories of migration. Another manifestation of this is the the relative ignorance that most of the population suffers from regarding this topic: Neoclassical models are known more than the alternatives, even though academically it is the Neoclassical one which has been mostly abandoned.