Some 1.3 million illegal immigrants have left the United States since Congress failed to pass comprehensive immigration reform in the summer of 2007. If the trend continues, according to a new study, the nation's illegal population will drop by half in the next five years.
Moreover, reports the Center for Immigration Studies, young Hispanic immigrants began heading south before the nation's economy did – a clue that what's driving the new outmigration is a stepped-up border and workplace enforcement, not a souring US job market.
The source of the report – a think tank with a record of opposing illegal and even some legal immigration – is controversial in immigrant communities. But its findings could help frame the debate in a new Congress and a new administration.
The key conclusion is that enforcement, not the economy, is driving the decision to self-deport.
"The dropoff in illegal immigration seems to occur before there is a runup in their unemployment rate," says Steven Camarota, director of research at the Center for Immigration Studies.
But Mr. Camarota also cites evidence of a link to the discussion in Congress about a path to legalization for undocumented workers. "From May to April  there is an actual uptick in the number of illegals in the country, which falls off after the legislation fails. It seems as if the discussion of legalization had some effect on the decision to come or go or both," he says.
Critics caution that little is known about a shadow workforce estimated at anywhere from 11 million to 20 million. "The problem is it's difficult to know what's causing a change like this," says Tamar Jacoby, president of ImmigrationWorks USA, an organization of employers nationwide lobbying for comprehensive immigration reform. "But the one thing we know for sure is that the country is in a deep economic downturn, if not a recession, which means there's much less need for workers, especially those providing services for the middle class."
"Immigration is a market-driven phenomenon and that's why immigration is beneficial to the economy," she says. "When we need them, they come; and when we don't, they go home. Has enforcement had some effect? Perhaps. But there's no question that the economic downturn would in and of itself have a huge effect in attracting fewer [illegal immigrants] and sending more home."
When the Senate fell short on its last vote on comprehensive immigration reform in June 2007, the takeaway message for politicians on both sides of the issue was this: Secure the borders first. Since then, the Department of Homeland Security has beefed up security along the southern border and reported a spike in the deportation of illegal immigrants – 285,000 in fiscal 2007 – and nearly 100 employers of illegal workers facing jail sentences and very substantial fines, also a record.
By the end of this year, the US border patrol will be the largest in history and twice the size it was when President Bush came to office, Homeland Security Secretary Michael Chertoff told a House panel on July 17.
"We've seen a turn of the tide in terms of illegal immigration," he told the House Homeland Security Committee, citing a "substantial" decline in apprehension of illegal immigrants crossing the border and reports that remittances through Mexico and other countries in Central America from the US are declining.
Anecdotal evidence supports that claim.
The Rev. Robin Hoover of Humane Borders in Tucson, Ariz., delivers water in the desert to help people survive the trek into the United States. "Without doubt, people have left, and without question fewer people are coming," he said in a phone interview, citing conversations with migrants on both sides of the border. He attributes the shift to extensive knowledge within the illegal immigrant communities of declining work prospects in the US.
"A lot of people doing the recruiting are friends, uncles, cousins, relatives. People crossing the border may not know what kind of work they will be doing, but they know it's work and there's somebody at the other end making the arrangement," he adds. "As I've said for years, the migrants on the South Side of Chicago know more about the economy than the US Labor Department."
Analysts at the Center for Immigration Studies note that there's always uncertainty when estimating the illegal population. Monthly data collected by the Census Bureau through May 2008 shows a significant decline in the number of less-educated, young Hispanic immigrants, but the authors note that in a climate of stepped-up enforcement, people may be more wary of answering a government survey. "This in turn could create the illusion that the illegal population is falling when in fact the population remains unchanged." But they add that other data – such as remittances home, border apprehensions, and school enrollment data – signal that illegal workers are leaving the country.
Other immigration experts note that there's a long-term correlation between immigration and the economy.
The difference is that if illegal workers are leaving their jobs because of a stepped-up enforcement, there's an opportunity for legal workers to take their place. If they're leaving because the jobs are disappearing, that's less the case, Mr. Malanga says. "With so many unskilled legal residents out of work, greater enforcement coming at a time of economic stress might afford these individuals an opportunity to find new jobs," he says.