Named the California Values Act (or SB 54) and set to take effect in January 2018, the law would provide discretion to state and local law enforcement to cooperate with federal immigration authorities when they detain a suspected undocumented immigrant.
Instead, the officers must try to arrest them at their homes or jobs out in the community - where their family or other illegal immigrants around them could also be arrested.
The signed bill prohibits ICE officers to question the immigration status of an immigrant, and counties will no longer be able to reserve ICE permanent desks in jails.
In a speech in Portland, Oregon, last month, he called this legislation "unconscionable".
The Trump Administration has been threatening to withhold federal funds from states that declare themselves as sanctuaries.
Well, it's official. California has become a sanctuary state and in doing so, unsurprisingly, has won the blue state race concerning who could give the Trump administration the middle finger first. Since then, 29 states and the District of Columbia have passed laws legalizing marijuana in some form. That policy was temporarily blocked by a federal judge after being challenged by the city of Chicago, Illinois.
The Department of Homeland Security's Immigration and Customs Enforcement agency rebuked Gov.
Meanwhile, the state law enforcement can only detain someone in a request from the federal government, notifying the latter to release or transfer someone to federal custody, after there's a felony warrant or the person has been convicted of one of the over 800 crimes listed on the bill. It also referred back to Brown's signing statement, in which he laid out what the bill does - and does not - do.
"California lawmakers are drawing their strength not from Trump, but from migrants who display a great deal of courage every single day", Alvarado said. There is strong symbolism in the move, although California governments' actions relative to individuals in the country illegally will change little in many parts of the state.
Pablo Alvarado, director of the National Day Laborer Organizing Network, said Trump seeks to cause distrust for political gain.
"The president will be laying out his responsible immigration plan over the next week", she said.
The announcement comes under the auspice of it being "safer" for ICE to "transfer" immigrants to detention facilities when the arrests are made at prisons rather than neighborhoods and worksites, framing mass detainment as a foregone conclusion. An estimated 10 million immigrants live in California, about 25 percent of whom are thought to be undocumented.
Bill Whalen, a longtime GOP strategist who is now a fellow at Stanford's Hoover Institution, said state and federal laws - such as marijuana legislation - often conflict.
A number of cities in California, such as Los Angeles and San Francisco, have already banned police officers from collaborating with ICE on operations to capture undocumented immigrants.