SACRAMENTO — Moments after California lawmakers passed a plan designed to undercut attempts by the president and fellow Republicans to keep control of Congress, Gov. Gavin Newsom said the state’s proposed partisan redistricting that favors Democrats is a necessary counterweight to President Trump’s threat to American democracy.

Trump’s assault on vote by mail and decision to send the military into U.S. cities are evidence of his authoritarian policies, and California must do its part to keep him in check, Newsom said.

By deploying federal immigration agents in roving street raids and activating thousands of members of the National Guard in Los Angeles and Washington, D.C., Newsom said, Trump is amassing “a private army for Donald Trump.”

“He’s trying to rig the election, he’s trying to set up the conditions where he can claim that the elections were not won fair and square,” Newsom said. “Open your eyes to what is going on in the United States of America in 2025.”

The argument is a preview of the messaging for the ballot measure campaign that Newsom and his Democratic Party allies will be running over the next 74 days.

On Thursday, California lawmakers signed off on a Nov. 4 special election that will put partisan redistricting in front of California voters.

The ballot measure, called Proposition 50, will ask voters to discard the congressional boundaries drawn by the state’s independent redistricting commission in 2021 in favor of partisan districts that could boot as many as five California Republicans out of Congress.

“When all things are equal, and we’re all playing by the same set of rules,” Newsom said, “there’s no question that the Republican Party will be the minority party in the House of Representatives next year.”

California is “responding to what occurred in Texas, we’re neutralizing what occurred, and we’re giving the American people a fair chance,” Newsom said.

National Republican Congressional Committee Chair Rep. Richard Hudson of North Carolina accused Newsom of trying to “rig” the system to advance his own political career.

“Instead of fixing the homelessness, crime, drug, and cost crises crushing the Golden State, Gavin Newsom is tearing up California’s Constitution to advance his presidential ambitions,” Hudson said in a statement.

California’s new lines would neutralize efforts in Texas to redraw their congressional district maps to help elect five more GOP candidates in 2026. The Texas Legislature is expected to approve new district lines this week.

The other option, Newsom said, is for California and Democrats to “roll over and do nothing.”

“I think people all across the country are going to campaign here in California for this,” Newsom said. “They recognize what’s at stake. It’s not just about the state of California. It’s about the United States of America. It’s about rigging the election. It’s about completely gutting the rules.”

Times staff writer Seema Mehta contributed to this report.