Becker is unquestionably correct that economic factors provide the principal explanation for the sharp drop in Mexican immigration in the last four years. Either higher unemployment in the United States or lower unemployment in Mexico would tend to reduce Mexican immigration to the United States, and the combination of both trends in recent years has made the fall in immigration steeper than it would have been had one but not both forces been at work. The unemployment rate is still almost 8 percent in the United States but it has fallen to 5 percent in Mexico.
Although the decline in Mexican immigration is a good illustration of the economics of immigration, its significance for both the United States and Mexico probably is small. The United States attracts more immigrants than any other country in the world, and if it wants to offset the decline in Mexican immigration with an increase in immigration from other countries (including other Central American countries), it can do so effortlessly. How many Mexicans live in the United States rather than in Mexico probably has little effect on Mexico either, since Mexicans living in the United States remit large amounts of money to their relatives in Mexico.
Just as financial capital moves more or less effortlessly across national borders in search of higher returns, human capital as well is increasingly mobile. The ability of Mexicans to work on either side of the U.S.-Mexican border benefits both the United States and Mexico. Immigration reform now being discussed in Congress will if enacted reduce barriers to the international movement of human capital even further, and can therefore be compared to the successful post-World War II movement for the reduction of tariff barriers to international trade.
The diminution in Mexican immigration to the United States has greater political than economic significance. It has reduced the hostility to immigrants, a hostility that played a role in the licking that the Republican Party took in last November’s national elections, and by reducing that hostility facilitates immigration reform.
I do not think we should return to the era, which ended in about 1920, of unrestricted immigration to the United States. What has changed since then is that the country is considerably more crowded, and with an existing population in excess of $300 million additional population contributes to pollution, water shortages, extinctions, other environmental harms, infrastructure costs, and traffic congestion. In addition, the expansion in public benefits in recent decades can attract immigrants from very poor countries who have little prospect of gainful employment. So immigration has to be regulated. But so for that matter so does international trade in products, services, and financial capital. The goal of U.S. immigration policy should not be to discourage or encourage immigration, but to admit as immigrants (besides refugees and family members) only persons who have good prospects for making a net contribution to the U.S. economy.
Because of the difficulty of policing our long border with Mexico effectively, our large population of illegal immigrants is largely Mexican. Illegal immigration drives many Americans crazy, although I’m not clear why. Most illegal immigrants are productive workers and receive few public benefits. Their expulsion is neither feasiible nor (because illegal immigrants are a significant part of the U.S. labor force) desirable from an economic standpoint. The diminution in Mexican immigration should make it easier to obtain meaningful reform of our immigration policies.