A battle is brewing over San Diego County’s new policy aimed at limiting the sheriff’s transfers of undocumented individuals into the custody of Immigration and Customs Enforcement, or ICE.

The San Diego County Board of Supervisors on Tuesday passed the measure to end the use of any county resources for immigration enforcement by a vote of 3-1.

The policy builds on Senate Bill 54, a state law known as the California Values Act that was passed in 2017 to limit state and local participation in deportations, with some exceptions for people convicted of crimes like assault and battery.

The Board’s new measure closes those exceptions, which Board Chair Nora Vargas called “loophole[s]” in introducing the policy. The measure ends voluntary transfers from the county into ICE custody, or notifications of anyone’s release from detention, requiring the federal agency to get a judicial warrant. Approximately 200 people were transferred from San Diego County into ICE custody last year.

Hours after the policy’s passage on Tuesday, Sheriff Kelly Martinez said in a statement she would not enforce it, noting she “will continue to follow state law and there is no loophole in state statute.”

“The Sheriff’s Office will not change its practices based on the Board resolution and policy that was passed at today’s meeting,” the statement from Martinez’s office reads in part. “The Board of Supervisors does not set policy for the Sheriff’s Office. The Sheriff, as an independently elected official, sets the policy for the Sheriff’s Office.”

“California law prohibits the Board of Supervisors from interfering with the independent, constitutionally and statutorily designated investigative functions of the Sheriff, and is clear that the Sheriff has the sole and exclusive authority to operate the county jails,” the statement concludes.

Advocates have long pushed for the new Board policy.

“We believe this is very important when it comes to ensuring public safety,” said Ian Seruelo, the chair of the San Diego Immigrant Rights Consortium, a coalition of advocacy groups.

“The only way for our communities to trust the local government and the local police is to show that our local police is separate and not part of ICE, is not part of immigration enforcement,” he said. “You may not want to report to the police if you think the police is part of ICE, right?”

On Thursday, Seruelo and the SDIRC sent a letter to Martinez, copying the County Board and California Attorney General Rob Bonta, urging her to comply with the new policy.

At issue is the clause within SB 54 that states, “A law enforcement official shall have discretion to cooperate with immigration authorities only if doing so would not violate any federal, state, or local law, or local policy.”

The SDIRC’s letter said “any transfer of notification that is made without a judicial warrant is a direct violation of state law,” because it would violate the new local policy.

“We hope that your statement was a mere misunderstanding on your part of the full scope of the California Values Act, and not a flagrant disregard for state law, our democratic processes and our constitutional rights,” the letter reads.

In response, Martinez again reiterated in a statement Friday, “The Sheriff’s Office will not be expanding nor changing anything we have been doing,” adding that the office “will continue to follow state law and maintain the way we have been operating for several years.”

“The sheriff’s department is saying, ‘Stop. That’s not the state law,’” said immigration attorney Esther Valdes Clayton. “We follow the state constitution and the government code. And the what the government code says is that we can cooperate when it comes to these particularly egregious crimes.”

Valdes Clayton said she believed the Board policy was a “largely symbolic resolution” to score political points before President-elect Donald Trump takes office in January.

“Why was this important to San Diegans?” she asked. “I think it was more important to the three Board of Supervisors and their political careers to have this go on paper and try to attempt to Trump-proof our community.”

Valdes Clayton noted she thought there would be several lawsuits over the policy, adding, “This is something that I believe the Department of Justice is going to have to clarify, all the way to the Supreme Court.”

Seruelo said he too believed lawsuits were a distinct possibility.

“We are ready to continue to be vigilant and to monitor the implementation of the resolution,” he said. “If the sheriff, you know, indeed refuses to follow the resolution and transfers any of our community members without any judicial warrant, then, you know, we may – if we will have to go file a lawsuit in this regard, we would. That would be one of our options, definitely.”

When asked about the conflict, Bonta’s office said in a statement in part, “it is our expectation is that all local law enforcement agencies comply with SB 54 and all applicable local policies enacted in accordance with SB 54.”

“In light of the President-elect’s threats of mass detention, arrests, and deportation, we are monitoring compliance closely; we will take a look at the facts of each scenario as it arises; and we will respond appropriately if we believe an agency is violating the law,” Bonta’s statement continued, pointing back to the county for issues of compliance with local policy.