In direct rebuke of President Trump’s effort to crack down on illegal immigration and attempt to boost deportation, California Gov. Jerry Brown signed legislation establishing the state as an official sanctuary on Oct. 5.

Senator Kevin de Leon (D-Los Angeles) authored the bill in late 2016 to prevent state law enforcement from cooperating with federal immigration, including U.S. Immigration and Customs Enforcement, or ICE. They also may not question immigrants on their current immigration status by way of this new legislation.

Under the new bill, state and local enforcement are also barred from detaining immigrants for the federal government without a warrant, participating in border patrol activities and detaining immigrants with only a civil immigration warrant.

In a signing message, Brown insisted the importance of a bill labeling California, which holds one of the largest immigrant populations in the country, as a sanctuary to persons living in a feared future.

The bill, taking effect this coming January, received early heat from opposing politicians, including Attorney General Jeff Sessions who went as far as urging Brown to oppose it.

White House Press Secretary Sarah Huckabee Sanders also criticized the bill and Brown himself, saying that “The president will be laying out his responsible immigration plan over the next week, and I hope that California will push back on their governor’s, I think, irresponsible decision moving forward.”

The signing of this new bill adds to continuing tension between Trump and the state of California, which has largely resisted the president’s aggressive immigration policies.

“These are uncertain times for undocumented Californians and their families, “said Brown. “And this bill strikes a balance that will protect public safety, while bringing a measure of comfort to those families who are now living in fear every day.”