LA JOLLA -- During his more than 40-year career as a researcher, professor Wayne Cornelius did what few politicians and policy-makers do when it comes to undocumented immigrants: He spoke to them to find out why they come here.

For decades, Cornelius has been a leading expert on Mexican migration to the United States. He retired last week as the director of the Center for Comparative Immigration Studies, an immigration research organization at UC San Diego.

Using detailed surveys, Cornelius and his students asked illegal immigrants here, and their families back home, why they migrated to the United States. The work has yielded volumes of information on the immigrants and the government policies that affected them.

A frequent critic of the federal government's strict border enforcement policies, Cornelius said few in Congress were willing to listen to what the research says.

"Many politicians have concluded that this is a lose-lose issue and whatever they support is going to offend some significant segment of their constituency," Cornelius said.

Cornelius, 64, began conducting field research in Mexico in 1962. His early work focused on Mexicans living in rural areas who migrated to large urban areas for work, he said.

In the mid-1970s, he began to study a rural community, Los Altos, Mexico, about 300 miles west of Mexico City. He noticed that many people in the community were migrating to the United States, and that is when he began studying Mexican migration patterns to the U.S.

Gordon Hanson, an economist at UCSD whose work also focuses on immigrants, called Cornelius a "pioneer" in immigration studies.

Cornelius' work has informed the often strident discussion about immigration reform in the county, Hanson said.

"People involved in the debate are aware of his work and he shapes the thinking about policy," Hanson said.

Angela Kelley, vice president for the Center for American Progress in Washington, D.C., a pro-immigrant group, said she hopes Cornelius will continue to advocate for policy changes.

For now, that's not what Cornelius has in mind, he said.

Last day

He plans to take a monthlong vacation in western Massachusetts to "decompress and unwind," Cornelius said. The stress of running a research center, and raising the half-million dollars a year it takes to run the facility, has taken its toll, he said.

"I'm burned out," he said last week sitting behind his desk opening his mail, which included his last paycheck.

The walls of his office were still adorned with books, awards and mementos. He had a Mexican wrestler's mask and a green U.S. Border Patrol baseball cap on his desk. He jokingly offered to put them both on for a picture.

In one corner of the room, La Nena, a therapy dog, licked at a bowl of water. Cornelius volunteers at Scripps hospitals, where the dog helps calm patients, he said.

After retiring, Cornelius said he plans to dedicate more time to volunteer efforts, including donating more time to his Episcopalian church. Cornelius, who was raised in western Pennsylvania, will continue to live in Del Mar, he said, mentor students and write books on immigration.

Before he arrived at UCSD, Cornelius taught political science at the Massachusetts Institute of Technology in the late 1970s.

In 1979, Cornelius founded the Center for U.S.-Mexican Studies, which conducts research on U.S.-Mexico relations, at UCSD. Later, he founded the Center for Comparative Immigration Studies and has served as its director since 1999.

'Not rocket science'

Since 2004, Cornelius has led the center's Mexican Migration Field Research and Training Program, which conducts annual field work in Mexican communities where illegal immigrants come from. They also study the U.S. communities where the immigrants settle.

In the program's most recent work, researchers studied the migration of members of an indigenous community, San Miguel Tlacotepec, in Oaxaca, Mexico, to the city of Vista.

Cornelius said he has found that the main reasons why people from Mexico come illegally to the U.S. are to work and to reunite with family members.

U.S. policy on illegal immigration has largely failed, Cornelius said, because it has focused mainly on border enforcement, such as fencing and increased patrols, without addressing the economic conditions that push people to come here, such as high unemployment and poverty in their home communities.

Speaking on what was officially his last day at work, Cornelius said politicians rarely take the time to understand the problem and are in search of a "quick fix," such as building a border fence or creating new ID cards.

Illegal immigration critics such as Mark Krikorian, executive director of the Center for Immigration Studies, an organization that advocates for stricter immigration polices, say border enforcement efforts can work if coupled with tough interior enforcement, such as at work sites.

The aim is "to make it as difficult and unpleasant as possible to live here illegally" and make illegal immigrants go home on their own, Krikorian wrote in a report. This way, the number of illegal immigrants will be reduced to "a manageable nuisance, rather than today's crisis."

Cornelius disagreed.

A more effective way to curb illegal immigration from Mexico, where most illegal immigrants come from, is to create jobs and improve the economy of the areas where they live, Cornelius said.

"It's not rocket science," he said. "It would take much less money than we're currently spending on border enforcement, interior enforcement, let alone the cost of implementing a new (ID card) system."

He added: "But it's very hard to get politicians interested in that because their time horizon is the next election. Creating jobs projects and stimulating the economy in the migrant-sending areas is something that would not produce results for at least a decade. That's too long for most elected officials."

Since the mid-1990s, the federal government has concentrated much of its efforts on beefing up the border, through programs such as Operation Gatekeeper, which focused on the San Diego area -- increasing funding to build a border fence from Imperial Beach to Otay Mesa and hiring more Border Patrol agents.

During that time frame, the number of Border Patrol agents has tripled from about 6,000 in 1996 to nearly 18,000 in 2008. The federal government's border security budget was $13 billion in 2008.

Unintended consequences

The federal government has replicated the Operation Gatekeeper program in other border areas in Arizona and Texas, but it has not reduced overall illegal immigration, Cornelius said. Illegal immigrants simply look for other routes where there is less vigilance, he said.

While it is harder to get across the border, most illegal immigrants eventually make it, Cornelius said.

In the surveys conducted by the center, the percentage of migrants polled who said they were able to successfully make it across has remained about the same since 2005 at between 92 and 98 percent.

The increased vigilance, Cornelius said, has had several unintended consequences.

It has increased the need to hire a smuggler to guide illegal immigrants through and thus increased the cost of hiring one, from less than $1,000 before 2001 to about $3,000 in 2009, according to the center's surveys.

It has reduced "circulatory migration," the pattern where illegal immigrants who came here to work returned home for the holidays or when jobs were scarce. That meant more and more illegal immigrants began settling in the U.S. permanently with their families, boosting the overall illegal immigrant population to about 12 million.

And it has helped increase the number of people who die attempting to cross the border illegally, Cornelius said. From 1995 to 2008, at least 5,046 bodies believed to be illegal immigrants have been found along the border, according to the center's reports.

Without addressing the conditions that lead people to risk their lives to come here illegally, Cornelius said, "there is very little that the government can do to affect the volume of migration."

Call staff writer Edward Sifuentes at 760-740-3511.