Dozens of participants in the rally outside San Francisco's immigration offices. Local authorities are afraid the program may be doing more harm than good.
Demonstrators called for the Secure Communities program to be thrown out.
The program works like this: If a person is arrested and sent to the county jail, fingerprints are taken and run through three databases. One of those databases belongs to the FBI, which in turn shares it with the Immigration and Customs Enforcement. If the person is undocumented, they are susceptible to deportation.
When the program was launched in 2000, it was meant only to identify and deport dangerous illegal immigrants, but ICE now admits most of those who have been deported under the program had minor or no criminal records.
"If someone is here illegally, they have to be dealt with," said Howard Epstein, the former chairman of the San Francisco Republican Party. "There are a lot of good people who are here illegally; still, we are a nation of laws and we have to know who's here."
But some police departments say at times immigrants refuse to cooperate or report crimes because now they fear they, too, will be taken and fingerprinted.
"We want people to know the police department is here to help," said Albie Esparza with the San Francisco Police Department, "if they are a victim of a crime, or if they witness a crime regardless of their immigration status."
While some counties would like to opt out of the program, the Department of Homeland Security announced this month it would not allow them to do so. ICE says it continues to work with law enforcement partners, and in a statement it added that it "plans to reach complete nationwide activation by 2013."
President Obama has called for an overhaul of the nation's immigration system. Still, advocates say the president hasn't done enough.