When the Department of Homeland Security reported their numbers in June, we discovered that they haven't apprehended so few illegal aliens since 1973. One wonders: Why is that?

Is it the U.S. economic downturn? Or mght it be beefed-up enforcement efforts?

Data from a research team led by Wayne Cornelius, Director of Center for Comparative Immigration Studies at the University of California, San Diego indicates that our strengthened border enforcement may be producing some unintended consequences

According to info they gleaned from thousands of interviews with migrants and prospective migrants, it seems it's the downturn of the U.S. job market along with the high personal and financial costs of migration that's slowing the rate of undocumented migration from Mexico.

But, at the same time, the undocumented immigrants who are already here are staying put. They want to avoid the great expense and physical risks of being smuggled back into the United States should they leave to go back home. They fear losing their U.S. jobs. And, besides that, there just aren't many economic opportunities to return to in Mexico.

The ironic reality that the data reveals is that enhanced border security has created "reduced circularity in migration." We've essentially locked illegal migrants into the United States because the prospect of going home and returning later has gotten too expensive and dangerous.

The main reason undocumented migration from Mexico has lessened, according to Cornelius´ research, is that there are fewer jobs available in the United States. Decreased numbers of illegal entrance apprehensions is not because they can't get in. Migrants attempting to enter the US illegally may be caught on their first attempt at crossing the border; however, they have an almost 100% chance of eventual success if they continue to try.

Apparently, the most profound impact that border enforcement has had on migrants in the past decade has been "reduced circularity in migration (less return migration)." Or, simply put: it looks like border enforcement is more successful at keeping undocumented immigrants in the United States than it is in deterring them from coming in the first place.

For further information: KEEPING MIGRANTS HERE: Recent Research Shows Unintended Consequences of U.S. Border Enforcement