The immigration dynamics were different in 2007, the last time members of Congress tried (and failed) to reform the U.S. immigration system. That year, the number of Mexicans living without authorization in America stood at nearly 7 million. In the half-dozen years following 2000, an average of a half-million Mexicans moved to the U.S. each year.

But Pew Research reported last year that net migration from Mexico to the U.S. reached a “standstill” in 2010. It may even have been negative, researchers concluded, as the stalling American economy induced workers back across the border.

Forty years after it began, the mass migration that brought roughly 12 million Mexican-born people to the U.S. has petered out. The question that Congress must answer, as it deliberates immigration reform legislation, is whether the immigration boom is over forever.

Questions about the future of Mexican migration trends loom large over Capitol Hill. The Senate-passed immigration reform bill, in its current draft, would give legal status to many undocumented immigrants and increase legal immigration in future years. It also includes a number of border security measures intended to win the support of lawmakers concerned about high levels of immigration, including provisions for dispatching up to 20,000 extra Border Patrol agents to the Southwest and extending the border fence to 700 miles total. Any bill that passes the House of Representatives is expected to place an even greater emphasis on securing the border.

Some commentators, such as the Washington Examiner’s Michael Barone, have suggested that the lowered trajectory Mexican immigration, legal and illegal, has rendered such border protections unnecessary. While analysts disagree about the future of U.S. immigration trends, they identify three factors that will determine whether the U.S. will ever see a major influx of Mexicans again: demographics, economics, and American immigration policy. The last factor is ultimately the most important for Congress to consider — the U.S. government controls the fate of its borders.



Michael Teitelbaum, a demographer with the Alfred P. Sloan Foundation, says that economic factors and law enforcement determine immigration levels in the short term, but long-run pressures are set by demographics.

Over the last generation, Mexico’s demographics have changed dramatically. The total fertility rate has fallen, from 6.5 children born to the average woman in the early ‘70s to 2.25 in 2013, according to the CIA’s World Factbook. A rate below 2.1 percent indicates a shrinking population.

Mexico’s rapidly declining fertility is no accident, suggests the Migration Policy Institute’s Eleanor Sohnen, who believes that the drop-off in Mexicans moving to the U.S. is a “long-term change.” Mexico’s demographic change reflects a concentrated campaign by the Mexican government to increase the availability of birth control and promote cultural acceptance of smaller families. It also is a product of Mexico undergoing a familiar demographic transition — progressing from a high-birthrate country to a low one as the economy modernizes.

High fertility can boost emigration by generating a situation in which there are simply more people than good jobs. Research suggests this demographic “push” explains as much as half of the illegal immigration from Mexico between 1970 and 2000, Federal Reserve Bank of Dallas economist Pia Orrenus told the Examiner.

Falling fertility, conversely, is expected to dampen emigration.

A drop in the fertility rate, however, might not show up in migration statistics until years later, when the smaller cohort has reached the typical age of immigration. The average newcomer to the U.S. is nearly 30 years old, according to the Center for Immigration Studies.

And while Mexicans have been having fewer babies and the population has been aging, the absolute number of Mexicans around the typical age of immigration is growing. The number of Mexicans under age 30 has increased from 62.9 million in 1995 to 66.7 million in 2010, according to the United Nations.

That large cohort of young Mexicans could mean high levels of Mexican-U.S. migration in the medium term. For its part, the Mexican government anticipates the number of its citizens moving to the U.S. each year rising back to about 325,000 in the next decade and staying near that level through 2050. James Smith, an economist at the RAND Corporation, calls it a “safe prediction” that Mexican-U.S. migration reverts to higher levels as the U.S. economy improves, and then tapers over the next two to three decades due to demographics.



Of course, how many young Mexicans feel compelled to leave their home country is also a function of the opportunities they are offered. If wages are low and jobs are scarce at home but high and plentiful in the U.S., then the prospect of emigration is more attractive.

Economic growth has been a big part of the recent slowdown in Mexican emigration, says Jesus Cañas, an economist at the Federal Reserve Bank of Dallas who monitors the Mexican economy.

Unlike in the U.S., the 2008 recession “wasn’t a financial crisis in Mexico,” Cañas says. The official unemployment never rose above 6 percent. By contrast, U.S. unemployment topped out at 10 percent in 2009.

And Cañas thinks Mexico’s economic gains are durable, thanks to a reform process that began with the independence of Mexico’s central bank in 1994. Mexico is poised for long-run growth, Cañas says, if — a big “if” — the political support for macroeconomic discipline is there.

In particular, Cañas says, private development of Mexico’s oil resources will boost the economy and the nation’s finances, much as production in the Eagle Ford Shale has enriched companies and the government in Texas. “That geology doesn’t stop at the border,” Cañas notes.

Because of the deep ties between migrants and their home country, Teitelbaum thinks the U.S. can expect Mexicans to move to the U.S. for more than a decade after the economic factors that originally spurred the exodus have dissipated. A 2010 Journal of Poverty study found that exposure to U.S. culture and media was a better predictor of Mexican youths’ intentions to migrate than socioeconomic status, and that the effect was even stronger in border cities like Juarez that are saturated by American media.

Nevertheless, the country’s economic success points to fewer Mexicans leaving in the future, all else equal.



Politics is the wild card. Mexican politics could crimp growth, and U.S. politics could ease laws regarding border security and undocumented residents.

According to Teitelbaum, governments’ efforts to keep people out are the “primary factor” in shaping immigration trends.

The number of potential immigrants to the U.S. remains enormous. The Census Bureau projects the number of foreign-born U.S. residents to increase by roughly 20 million in the next 20 years. And according to the Congressional Budget Office, immigration to the U.S. would rise by a further 16 million in the same time frame if the Senate reform bill is enacted, driven by greater legal immigration.

Those numbers don’t indicate the country of origin, but it’s easy to imagine high levels of immigration from places other than Mexico.

Already, the countries making up Central America’s Northern Triangle — Honduras, El Salvador, and Guatemala — are poised to make up the next wave of immigration to the U.S. In the last few years, Salvadorans passed Cubans as the second-largest immigrant group from Latin America, totaling 1.2 million people in the 2010 American Community Survey.

Of course, unlike Mexico, those countries do not share a border with the U.S.

“While there are many Central Americans who want to migrate north, they face much greater obstacles and costs than Mexicans,” Orrenus notes. Potential migrants from Guatemala or the Honduras to the U.S. must confront crime syndicates in Mexico, making their trips “long and dangerous,” and about twice as expensive as it is for Mexicans.

The obstacles — geographic and political — that dissuade border crossers are ultimately the determinant in the overall level of immigration to the U.S. That’s why Teitelbaum suggests that U.S. policy, even more so than Mexican demographics, is the key to future immigration levels.

Dozens, if not hundreds, of millions of people across the world would be willing to uproot their own lives to move to America if given the chance, a fact that won’t change anytime soon. Whether or not they come from Mexico or elsewhere, and in what numbers, is ultimately up to America.