Mayor Martin J. Walsh declared Wednesday he would sign a city ordinance to prohibit Boston police from detaining illegal immigrants for possible deportation, unless they were convicted of a serious crime.
The proposal is still in its early stages, but Walsh's announcement to a jubilant convention of mostly immigrant union delegates at the Hynes Convention Center drew a standing ovation and some tears, even as critics warned that the plan could backfire and lead to the release of dangerous criminals.
Walsh said he expected Boston would pass its own version of the Trust Act, legislation that is emerging nationwide as a way to limit the immigrants that state and local police turn over to US Immigration and Customs Enforcement after an arrest or traffic stop. Walsh said City Councilor Josh Zakim would file legislation this week to make clear that police should not detain immigrants for ICE after a judge has released them, unless the immigrants "have committed serious crimes."
"I'm assuming the council is going to pass the Trust Act, and I'm going to sign the Trust Act," Walsh said in remarks to reporters as he attended an event at a Boston school Wednesday night. Walsh, the son of Irish immigrants, added, "Many people who are in this country are undocumented. I'm certainly not going to have my police department picking up every single person in the country, state, or the city that's undocumented."
Though Walsh said last year he supported the Trust Act, his speech Wednesday marked a departure from the past administration of Mayor Thomas M. Menino. In 2008, Boston was one of the first cities to launch the Secure Communities program, which lets federal agents check the fingerprints of anyone arrested by state and local police. ICE can then ask police to detain immigrants for up to 48 hours after they are released so that immigration officials can take them into custody.
City officials had argued that Secure Communities helped rid Boston of gang members and other criminals. But federal statistics showed nearly half the 757 deportees from Boston and Suffolk County from 2008 through March had no criminal record. Nationwide, only 20 percent of deportees had no record.
Advocates for immigrants hailed the news Wednesday. Many have said Boston's policies had made immigrants afraid to report crimes.
"We're thrilled," said Brian Lang, president of Unite Here Local 26 in Boston, and who introduced Walsh before he announced the proposal to 1,000 union delegates attending an international convention of restaurant and hospitality workers. "As a union, we think this is a central issue for worker's rights."
"It's sending a very important message, not just to the rest of the state, but to the rest of the country," said Patricia Montes, executive director of Centro Presente, a statewide immigrant group based in Somerville.
But critics say Walsh's push frustrates efforts to get federal and local law enforcement agencies to work together better, especially after the Sept. 11, 2001, terror attacks and last year's Boston Marathon bombings.
Jessica Vaughan, director of policy studies for the Center for Immigration Studies, a Washington think tank, said failing to report illegal immigrants opens the door to future crimes. In 2008, a Salvadoran man with a criminal record killed three members of the same family in San Francisco. In 2011, a man from Ecuador with a record brutally murdered a Brockton woman and her son.
"What is Mayor Walsh going to say to the family member of somebody who gets killed or maimed or raped by a criminal alien who should have been held by Boston police but was let go because of this ordinance?" she said.
Zakim countered that immigrants accused of crimes must first clear the criminal justice system. If a judge releases them, he said, then ICE can pick them up. But, under his plan, the city will no longer pay to jail them for ICE.
"Boston has a rightfully earned a reputation as a place that's welcoming and open to everyone," Zakim said in a telephone interview. He added, "To hold someone at city expense for a civil violation just seems unnecessary and not the way Boston should be."
Though ICE has always been able to jail immigrants, the Secure Communities technology dramatically enhanced the federal agency's ability to detect illegal immigrants through state and local police. In 2012, over Governor Deval Patrick's objections, ICE expanded the program across Massachusetts, and it is now operating nationwide.
In recent years, however, advocates for immigrants have chipped away at ICE's ability to detain immigrants, many passing their own versions of the "Trust Act."
Last year, Connecticut and California passed state laws limiting detainers, joining more than 100 jurisdictions nationwide that are curbing their cooperation with ICE, according to immigrant advocacy groups tracking the legislation.
In May, Somerville became the first Massachusetts city to limit ICE detainers to immigrants accused of or convicted of a serious crime.
Zakim said he would limit detainers only to immigrants convicted of serious crimes.
A bill is also pending in the state Legislature that would limit ICE detainers statewide to adult immigrants who have served at least five years in prison.
Boston is now home to 167,000 immigrants, about 26 percent of the city, according to the census, and slightly more than half are not US citizens, a likely mix of immigrants here legally and illegally.
ICE officials did not respond to a request for comment.