California Gov. Gavin Newsom is warning President Donald Trump and Republican governors that if they go forward with redistricting proposals, he will also implement mid-decade redistricting efforts in his state.

In a letter to the president Monday, Newsom said California “cannot stand idly by” as Texas — and other GOP-led states — attempt to follow Trump’s directive to create Republican-favored congressional maps.

“If you will not stand down, I will be forced to lead an effort to redraw the maps in California to offset the rigging of maps in red states,” Newsom said. “But if the other states call off their redistricting efforts, we will happily do the same. And American democracy will be better for it.”

The White House did not immediately respond to a request for comment.

Newsom’s letter comes as the battle over the Texas congressional map has begun to spread to other states, including Indiana.

With Democrats needing to flip just three seats to reclaim a House majority, Trump pressed the Texas Legislature to draw a new map that would give Republicans an additional five congressional seats. Democrats around the nation condemned the effort even as Texas officials began to move forward with a plan. Texas Democrats have left the state to avoid voting on the new map, with some settling indefinitely in California.

Vice President JD Vance, meanwhile, headed to Indiana last week to urge Republicans in the Hoosier state to also create a new map. Separately, Ohio is mandated to redraw districts in the state, while talks are underway in Missouri, New Hampshire, South Carolina and Florida. In total, Republicans could gain 10 or more seats ahead of the midterms.

Newsom on Monday called the efforts “hyper-partisan” and an attempt to “rig” upcoming midterm elections.

“You are playing with fire, risking the destabilization of our democracy, while knowing that California can neutralize any gains you hope to make,” Newsom wrote. “This attempt to rig congressional maps to hold onto power before a single vote is cast in the 2026 election is an affront to American democracy.”

While Democrats have previously threatened to gerrymander their own maps if Republicans move forward with theirs, no moves have been made yet.

In his letter, Newsom said district maps should be drawn by “independent, citizen-led efforts.”