While the immigration debate in the United States is largely focused on the U.S.-Mexico border, an article from National Geographic looks a bit farther to the south. An estimated 400,000 migrants from Central America cross the border into Mexico every year, and though some stay to work in Mexico, most are headed for the U.S.

The economic prosperity of the U.S. has a strong pull effect on the Latin American poor, and the money that migrant workers send home to their families is having an increasingly large impact on their national economies. In Honduras, for example, remittances sent home from the U.S. made up one-fifth of the country’s gross national income in 2006.

“There is no solution to this,” a former Chiapas state official said wearily, after ticking off a list of southern border upgrade programs that have fizzled into ineffectiveness over the past decade. “You can put all the control measures down there that you want, but it’s not going to be fixed. The solution is to eliminate poverty.”