Why Illegal Immigrants Fear Leaving

As security tightened on the U.S. side of the border -- new barriers were built and it was flooded with Border Patrol agents -- a return to central Mexico to visit his wife and child carried the risk that he might not be able to get back to his job in Phoenix.

It made the difficult decision to have his family join him here easier.

Studies show that because it is harder to crisscross the border, illegal immigrants who intended to be in the U.S. for limited stretches may increasingly be choosing to bring their families with them -- and settle permanently.

Today, Severino and his wife own an avocado-colored four-bedroom ranch house in a suburb, where their 9-year-old son, Diego, attends school. Fearing possible deportation, they agreed to be identified only by Alejandro's mother's last name. Their story is typical.

"A hundred people come from Mexico to the U.S., but only 20 go from the U.S. to Mexico," Severino said. "If you return, the border is more dangerous now than ever. How will you get back?"

Mexican government surveys show that 20% of illegal Mexican immigrants returned home after six months in 1992, compared with 7% in 2000.

"The net effect of the militarization of the border since 1993 has been to transform a circular movement of male workers to a settled population of families," said Douglas S. Massey, a Princeton University sociologist who has long studied the phenomenon. "Once they're here, they hunker down to stay longer."

Massey and other analysts argue that if Congress tightens border security again, more illegal immigrants will put down roots in the U.S.

"Every time we try to solve this problem, we end up shooting ourselves in the foot," said Dawn McClaren, an economist at Arizona State University in Tempe who studies immigration issues.

Advocates of greater border security acknowledge that it may cause some immigrants to stay permanently in the U.S. But they cite census data showing that for 30 years -- well before the border was tightened -- increasing numbers of people born in Mexico were settling in the United States.

Other factors, they contend, have been more important in pushing the number of illegal immigrants to more than 11 million.