After nearly a decade of delays, federal officials began allowing the visas en masse only early last year, after sustained efforts from immigrant rights groups, particularly several based in Oakland and San Francisco. The pace of approvals has since stepped up, as has the controversy, with both defense lawyers and groups opposed to immigration contending that the process invites scams.

For millions of immigrants and their supporters, however, the program is truly an island of niceness, as Catherine Ward-Seitz, the regional immigration coordinator for Bay Area Legal Aid in San Francisco, put it. With a soured economy encouraging hostility at worst and apathy at best toward illegal immigrants, the U visas are a bittersweet consolation prize.

In a compassionate twist on the idea that felons should be imprisoned, victims who can show that guns (or knives or fists) were used against them can be released from the fear of deportation.

While victims of several specified crimes are eligible, at least three-fourths of the applicants for U visas to date, like the Guatemalan baby sitter, who asked that her name not be used for fear of retaliation from her spouse, say they have suffered domestic violence, said Chris Rhatigan, a spokeswoman for the United States Citizenship and Immigration Services. Immigration lawyers said this was largely because of the prevalence of domestic violence in general.

Ending impunity in cases of domestic violence makes whole communities safer, proponents say.

"These are disclosure-driven crimes, meaning people have to come forth and report them; there's no gunshot to bring it to our attention," said Lt. Kevin Wiley, commander of the Oakland Police Department's special victims unit, which certified 153 U visas last year.

"It's all about building trust," Lieutenant Wiley said, adding that police certification of the visas was a powerful tool in creating bonds among wary residents who have long been the silent victims of a range of crimes, like the robberies of illegal immigrants known on the streets as "amigo checkings."

What is more, Lieutenant Wiley said, the police often discover that domestic violence offenders have multiple victims.

Advertisement Continue reading the main story

Congress approved an annual limit of 10,000 U visas. Yet the regulations that would put the law in force were not made final by the Department of Homeland Security until September 2007.

Photo

A few dozen U visas were approved in 2008. Then the pace increased. In the fiscal year ending last September, immigration officials approved 5,825. Another 2,244 were approved in October and November. More than 10,000 applications are pending.

Ms. Rhatigan said the long delay resulted mostly from the complexity of the new rules, although some immigration advocates say the change of administrations in Washington played a part.

Lawyers defending clients on the other side of the visa petitions worry that the incentives of a U visa are creating new wrongs as well as righting old ones.

Newsletter Sign Up Continue reading the main story Please verify you're not a robot by clicking the box. Invalid email address. Please re-enter. You must select a newsletter to subscribe to. Sign Up You will receive emails containing news content , updates and promotions from The New York Times. You may opt-out at any time. You agree to receive occasional updates and special offers for The New York Times's products and services. Thank you for subscribing. An error has occurred. Please try again later. View all New York Times newsletters.

Marin County's deputy public defender, Tamara Chellam, argued that the U visas might create irresistible incentives for people to invent or exaggerate offenses. A recent client of Ms. Chellam is married to a woman who applied for a U visa while fighting her spouse for custody of their daughter. The woman testified that in early 2008, the defendant followed her to work at 5 a.m. and broke the window of her car. Although there were no other witnesses, the husband was convicted of stalking and assault. Ms. Chellam said she expected him to be deported on his release from prison.

A decade earlier, the woman had reported that her husband had abused her but subsequently said she wanted to drop charges, Ms. Chellam said. She applied for a U visa in 2007 on the basis of that incident, but court testimony revealed she had worried that it would not suffice because victims are required to cooperate continuously. Ms. Chellam said she suspected that the wife had tailored the 2008 incident to help support her subsequent successful application for a visa.

"The U visa offers a wonderful opportunity when used appropriately, but it can be lopsided and misused," Ms. Chellam said. "If a person wants to get rid of a spouse fighting for custody, or a rival gang member, these visas are very convenient, while the people on the other side can lose everything: their children, their jobs, their liberty and their right to stay here."

On the other hand, applicants for