Concerned that opponents will block or gut a federal immigration bill in the Congress, Sonoma County immigration advocates are now marshaling efforts to pass a bill in Sacramento that would reduce deportations of people held in local jails.

They are lobbying local officials to support the TRUST Act, which would prohibit local police agencies from holding individuals on federal immigration detainers unless they are charged or convicted of a serious felony or certain misdemeanors.

However, advocates say a big obstacle is Sonoma County Sheriff Steve Freitas, who opposes the legislation because he said it would force him to defy federal regulations.

The immigration holds are a key tool used in implementing the federal government's controversial Secure Communities program, which critics say casts a wide net that sometimes ensnares U.S. citizens, legal immigrants and undocumented immigrants jailed for minor offenses or charges that are later dropped.

Freitas was out of town on vacation this week and could not be reached for comment. Assistant Sonoma County Sheriff Lorenzo Due?s said the sheriff has not changed his position since last summer and still opposes the state legislation.

Under Secure Communities, fingerprints and other biometric data of every person booked into county jails are checked against federal law enforcement databases and those of the U.S. Department of Homeland Security. Federal immigration officials are alerted in cases where an individual has a possible immigration violation.

In such cases, ICE agents seek a federal detainer, or immigration hold, of up to 48 hours beyond the time when a individual would be otherwise released from jail.

The TRUST Act, authored by Assemblyman Tom Ammiano, D-San Francisco, would limit immigration holds to serious offenders. An immigrant arrested on suspicion of a "straight misdemeanor" or a prior federal deportation order would not be subject to an immigration hold.

The legislation is similar to a bill vetoed by Gov. Jerry Brown last summer. The new bill was approved by the Assembly in May and currently awaits a vote in the state Senate.

Carlos Alcal? a spokesman for Ammiano, said the legislation was recently amended in the Senate Public Safety committee to address a number of concerns raised by Brown.

"In June we got something from the Governor's Office saying this is what we want," Alcal?said.

Amendments essentially increase the number of crimes for which local sheriffs can hold people under ICE requests, he said.

The bill, AB 1081, can be taken up for a vote anytime after senators return from recess on Aug. 12, Alcal?said.

"We think we're in a good position to pass it in the Senate and send to the governor," he said.

Richard Coshnear, a local immigration attorney and member of the Committee for Immigrant Rights of Sonoma County, said campaigning for passage of the TRUST Act is becoming more imperative with U.S House Republicans lining up to either kill the federal immigration overhaul or make it more "draconian."

"Even in the (U.S.) Senate we're not very happy with the legislation being proposed," he said.

Millions of undocumented immigrants would likely not qualify and end up at greater risk of deportation through stepped-up enforcement efforts both in the workplace and at the border, Coshnear said.

Even those who would qualify under the Senate bill are today being deported, he said.

"We have decided we want to focus on the deportations issue and press Sacramento and Washington to make life livable for people who are now undocumented and for people who may remain undocumented despite a reform bill," Coshnear said.

"This, of course, will impact families where some are in and others are out," he said.