On the campaign trail last year, Donald Trump promised that he was not going to tolerate left-wing lawlessness on American streets and would use the full force of his presidential powers in response.

The protests against Immigration and Customs Enforcement (ICE) efforts in California on Saturday night gave him an opening to follow through on that promise.

Never mind that the Los Angeles Police Department (LAPD) said that the protests were largely peaceful, or that local authorities said they could handle the clashes that did turn violent.

Trump administration officials said that immigration agents were being targeted and injured ? and that local law enforcement had been too slow to respond.

"Waiting several hours for LAPD to show up - or them telling us that they're not going to back us up until they have an officer in a dangerous situation - is something that just isn't workable when you have violent protests going on," Homeland Security Secretary Kirsty Noem told CBS News on Sunday morning.

The LAPD said it "acted as swiftly as conditions safely allowed" and began dispersing crowds within 55 minutes of receiving the call.

Over California Governor Gavin Newsom's objection, Trump federalised the 2,000 California National Guard soldiers, and Defence Secretary Pete Hegseth warned that US Marines were also on "high alert" to deploy ? which would mark a rare use of the active duty military on US soil.

By Sunday morning, Trump was declaring victory and thanking the National Guard for restoring peace, even though the guard had yet to fully assemble.

The speed with which Trump reacted suggests that this is a fight his administration is prepared for ? and even eager to have.

The White House believes that law and order, and aggressive immigration enforcement, are winning issues for him.

His actions will thrill his core base of supporters and could sway political independents concerned about public safety.

Noem, in her interview, said the Black Lives Matters protests of 2020 in Minnesota were allowed to spread unchecked ? and that the new Trump administration was going to handle things differently.

"We're not going to let a repeat of 2020 happen," she said.

Democrats, however, have said the administration's use of masked immigration officers with military gear to arrest civilians in restaurants and shops has been inflammatory, and that the president's eagerness to deploy trained soldiers was unwarranted.

"For the president to do this when it wasn't requested, breaking with generations of tradition, is only going to incite the situation and make things worse," said New Jersey Senator Cory Booker.

"A lot of these peaceful protests are being generated because the president of the United States is sowing chaos and confusion by arresting people who are showing up for their immigration hearings, who are trying to abide by the law."

The US has a long tradition of summer protests, and it is only early June.

Five months into Trump's second term, these California demonstrations may be an isolated event ? or the start of greater civil unrest in the days ahead. (BBC)

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