LOS ANGELES, United States, June 11, 2025 (BSS/AFP) - California Governor Gavin Newsom went on the political offensive Tuesday with a dire warning that Donald Trump's crackdown on California "will not end here," attacking the president's policies across the country.

Newsom, who observers say is weighing a presidential run in 2028, has been full-throated in his insistence that Trump overstepped his authority by deploying troops to Los Angeles to quell days of unruly protests against immigration raids.

But on Tuesday he went well beyond accusing the president of stoking tensions in the country's second-biggest city to attack Trump's ongoing, polarizing effort to "Make America Great Again."

"California may be first, but it clearly will not end here," Newsom warned in the live-streamed address.

Trump, he said, is a "president who wants to be bound by no law or constitution, perpetuating a unified assault on American tradition."

The actions of immigration agents -- who Newsom said had used unmarked cars to detain a heavily pregnant US citizen and a four-year-old girl -- are worrying precepts of the administration.

"If some of us can be snatched off the streets without a warrant, based only on suspicion or skin color, then none of us are safe," he said.

"Authoritarian regimes begin by targeting people who are least able to defend themselves. But they do not stop there."

Newsom ran through a stark list of the Republican leader's actions since he returned to the White House in January, from firing government watchdogs to threatening universities' funding and targeting law firms.

"He's declared a war, a war on culture, on history, on science, on knowledge itself," the 57-year-old Democrat said.

This weekend, Trump will spend his 79th birthday watching tanks rumble through Washington at a parade to mark the 250th anniversary of the US army.

Newsom accused him of "forcing" the military "to put on a vulgar display to celebrate his birthday, just as other failed dictators have done in the past."

He charged Trump with "taking a wrecking ball" to American democracy, and said there were "no longer any checks and balances" on the president.

"Congress is nowhere to be found," Newsom said.

He called on Americans to "stand up and be held to account," but urged any protesters to do so peacefully.

"I know many of you are feeling deep anxiety, stress and fear," he said.

"What Donald Trump wants most is your fealty, your silence, to be complicit in this moment. Do not give in to him."

A presumed frontrunner for Democratic leadership, Newsom has made no secret of his political ambitions and has not shied away from a public showdown with Trump.

In the five days since the Los Angeles protests began, he has brawled with officials on social media and dared the Trump administration to make good on its threats to arrest him.