The plan was the most prominent of several pieces of legislation approved this week aimed at strengthening the rights of immigrants in California. But it also brought new protests from critics who say the state is protecting undocumented workers at the expense of federal immigration laws.

The bill, sent to Gov. Jerry Brown late Thursday, comes after some of California’s top law enforcement officials including Los Angeles Police Chief Charlie Beck and L.A. County Sheriff Lee Baca expressed strong support for the idea. They argued that immigrants should not fear cooperating with police or feel harassed simply because of their immigration status.

Activists have complained for years that undocumented immigrants stopped at drunk-driving checkpoints have had their cars impounded even if the drivers are sober because they don’t have valid licenses. Police also say these immigrants, unable to get car insurance, are involved in more hit-and-run accidents.

Kim Raney, president of the California Police Chiefs Assn., said his organization backed the plan only after it was amended to add various security measures. His biggest concern was that the driver’s licenses could be used as identification for air travel, potentially causing problems for federal security agencies.

“These licenses will include a special watermark on the front and language on the back that makes it clear this license is for driving only and not identification,” said Raney, who is also the police chief of Covina. “TSA and federal officials and law enforcement will all be aware that these grant driving privileges only and aren’t confirmed identification.”

Raney said the plan should put an end to many of the headaches police departments deal with concerning unlicensed immigrant drivers.

“You either have a license or you don’t have a license. You have no reason not to be insured,” he added. “This should end the entire debate over impounds.”

But the larger debate about how immigration laws are enforced is far from over.

Mark Krikorian of the Center for Immigration Studies in Washington said the California plan amounted to a “quasi-amnesty.”

“The whole point of immigration law is to make it impractical to stay here illegally,” he said. “This is doing the exact opposite. The point of this is to make it practical to live here illegally…. What it means is the government is formally incorporating illegal aliens into institutions of our society.”

Indeed, backing from law enforcement is far from universal. Kern County Sheriff Donny Youngblood, who has spoken against giving undocumented immigrants licenses, said Friday his position had not changed.

“I just think that if someone is in the country illegally, for us to give them a legal ability to drive makes absolutely no sense,” he said. “That … really bothers me.”

Youngblood challenged the idea that giving undocumented immigrants driver’s licenses would eliminate insurance issues in hit-and-run or other collisions. A license is no guarantee the driver would carry insurance, he said.

“It’s not with our citizens,” he said, “so how could it be with people in the country illegally?”

LAPD Chief Beck on Friday called the bill “a big step forward in making our roads safer.”

Beck has been an outspoken supporter of issuing driver’s licenses to immigrants in the country illegally, arguing it would reduce the number of hit-and-runs because such immigrants would have less fear of being caught for driving without having insurance.

Over the last few years, Beck and the L.A. Police Commission have moved to ease rules for when police officers impound the cars of those in the country illegally.

That move was opposed by the Los Angeles Police Protective League, which represents rank-and-file officers. The union argued that the new policy violated state law by stripping officers’ discretion to impound cars. The union, along with Judicial Watch in Washington, sued the city to have the policy tossed out. In August, a judge ruled the LAPD policy illegal but did not immediately strike it down, allowing it to remain in effect pending appeals.

Judicial Watch President Tom Fitton said that if the driver’s license bill is signed, the U.S. Justice Department will review whether it undermines federal immigration laws.