“The resistance that started in the Democrat party - this is the Republican resistance right here”, Republican Assemblywoman Melissa Melendez told Mr Trump.
Multiple California jurisdictions have formally registered their opposition to the law, and Orange County and San Diego County - both large populations hubs in southern California - have moved to join the Trump administration’s lawsuit against it.
California has long been a foil for the Trump administration, suing the federal government multiple times. Its Democrat-controlled legislature reacted to Mr Trump’s election by enacting protections for undocumented immigrants like the “sanctuary” law curtailing cooperation between local police and immigration enforcement.
The president has regularly condemned the state’s liberal leadership, and he has urged on conservative areas that have broken away - including by giving their leaders the prominent platform of a White House summit.
During a meeting with sympathetic California conservatives, he hailed a “rebellion by patriotic citizens who want their families protected and their borders secured” and lauded conservatives who had “bravely resisted California's deadly and unconstitutional sanctuary state laws”.
He also renewed his warnings that California’s laws were undercutting public safety, blasting the state for “providing safe harbour to some of the most vicious and violent offenders on earth”, adding of some immigrants, “these aren't people - these are animals”.
The latter comment drew a rebuke from James Martin, a prominent Jesuit priest and author, who warned Mr Trump's words were “the same kind of language that led to the extermination of Jews ('vermin') in Germany and of Tutsi ('cockroaches') in Rwanda”.
“This kind of language cannot be normalized. It is a grave sin”, Father Martin said on Twitter.
Calling people animals is sinful. Every human being has infinite dignity. Moreover, this is the same kind of language that led to the extermination of Jews ("vermin") in Germany and of Tutsi ("cockroaches") in Rwanda. This kind of language cannot be normalized. It is a grave sin. https://t.co/5VvURONwvh— James Martin, SJ (@JamesMartinSJ) May 16, 2018
While Mr Trump and administration officials warn the sanctuary law encourages lawlessness and protects dangerous criminals, the sanctuary law contains broad exceptions for violent offenders, allowing local law enforcement to work with federal authorities when detained immigrants have committed serious crimes.
California Gov Jerry Brown has accused the Trump administration of lying about the law's intent and substance, and the Democratic governor again blasted Mr Trump for what he called a political ploy.
“Trump is lying on immigration, lying about crime and lying about the laws of California”, Mr Brown said in a statement. “Flying in a dozen Republican politicians to flatter him and praise his reckless policies changes nothing. We, the citizens of the fifth largest economy in the world, are not impressed”.
Among California Democrats who have drawn Mr Trump’s ire, Oakland mayor Libby Schaaf has emerged as a favourite target after she warned residents of an impending immigration sweep. The president again lambasted her and suggested she should face charges.
“I would recommend that you look into obstruction of justice for the mayor of Oakland”, Mr Trump said. “Perhaps the Department of Justice can look into that”.