Democrats struggling to cope with the Trump juggernaut found some rare footing Thursday courtesy of the governor of California, Gavin Newsom, who ramped up his online mockery of the 47th president and promised a full-on counterassault to Republican plans to redraw congressional districts ahead of next year’s midterm elections.  

During what was sarcastically billed — in the style of one of President Trump’s social media posts — as a “historic press conference” featuring a handful of California’s Democratic leaders and their allies from groups such as Planned Parenthood, Mr. Newsom told rally goers to “wake up.”

“These are sober times,” he said. “Today is liberation day in the state of California. … Donald Trump, you have poked the bear, and we will punch back.” 

“We cannot unilaterally disarm, we can’t stand back and let this democracy disappear district-by-district all across this country,” he said. “We need to stand up, not just California, other blue states need to stand up.”

As the rally got under way, videos surfaced on X showing Border Patrol agents gathered outside the venue. The agent who oversees Border Patrol operations in California, Greg Bovino, told reporters, “We’re here making Los Angeles a safer place, since we don’t have politicians who will do that, we do that ourselves.”

Mr. Newsom’s press team shared videos of the agents on social media and wrote, “TRUMP’S PRIVATE ARMY IS ILLEGALLY ON PRIVATE PROPERTY!!!! WE WILL NOT BE INTIMIDATED BY THIS WEAK LITTLE MAN!!!”

Mr. Newsom insisted that his plan to redraw California’s congressional districts in time for next year’s midterms is more transparent and democratic than the move by Republicans in Texas, as the maps will be put up for a vote as a constitutional amendment, leaving it up to Californians to approve them. After the 2030 census, the state’s independent redistricting commission will resume its job of drawing congressional maps. 

He said Mr. Trump is pushing for Republicans to redraw political maps because the president fears his tenure “de facto ends” if Democrats take back the House in 2026. “He’s a failed president. Who else sends ICE at the same time we’re having a conversation like this? Someone who’s weak. Someone who’s broken. Someone whose weakness is masquerading as strength,” Mr. Newsom said.

Mr. Newsom and his staff spent the first part of the week trolling Mr. Trump on social media, with the apparent hope of nudging him to call off the Republican plans. His press team repeatedly sought to mimic Mr. Trump’s unique style of social media posts, and posted several messages in all caps featuring insults, nicknames, warnings, lots of exclamation points, and the president’s signature sign-off.

“DONNIE J. AND KaroLYIN’ LEAVITT WILL HAVE THEIR (LITTLE) HANDS ‘FULL’ TODAY. WHOOPS. I, GAVIN CHRISTOPHER NEWSOM, AMERICA’S FAVORITE GOVERNOR (MANY SAY), WILL HOST THE GREATEST PRESS CONFERENCE OF ALL TIME. AFTER THAT — ‘THE MAPS’ WILL SOON BE RELEASED,” the press account posted Thursday morning. 

In a separate post, the governor’s office appeared to suggest that Democrats would impeach and convict Mr. Trump, writing that he will “soon not be ‘47’” and that “patriots will take back Congress.”

While Thursday’s event was billed as the launch of a democracy-saving effort by Democrats who have used gerrymandering and redistricting as a political power play for decades, a recent Politico-Citrin Center-Possibility Lab survey found that by a two-to-one margin, voters in California said they want the current independent commission to retain its authority over the map-drawing process. Just 36 percent of voters said they approve of the idea of giving lawmakers the authority to draw the congressional maps. 

In a statement, a spokesman for the Republican National Committee, Christian Martinez, called California’s redistricting push a “stunt” that has “nothing to do with Californians and everything to do with consolidating radical Democrat power, silencing California voters, and propping up his pathetic 2028 presidential pipe dream.”

When asked about the social media troll campaign and whether it is a “strategy,” Mr. Newsom said, “I hope it’s a wake-up call for the president. I’m just following his example. If you have issues with what I’m putting out, you sure as hell should have concerns with what he’s putting out as president.”

“I think the deeper question is: How have we allowed the normalization of his tweets — Truth Social posts — over the course of the last several years to go without similar scrutiny,” he said.