LOS ANGELES (AP) — The Justice Department on Thursday sued to block new congressional district boundaries approved by California voters last week, joining a court battle that could help determine which party wins control of the U.S. House in 2026.

The complaint filed in California federal court targets the new congressional map pushed by Democratic Gov. Gavin Newsom in response to a similar Republican-led effort in Texas backed by President Donald Trump. It sets the stage for a high-stakes legal and political fight between the Republican administration and the Democratic governor, who's seen as a likely 2028 presidential contender.

“California’s redistricting scheme is a brazen power grab that tramples on civil rights and mocks the democratic process,” Attorney General Pam Bondi said in an emailed statement. “Governor Newsom’s attempt to entrench one-party rule and silence millions of Californians will not stand.”

Newsom spokesperson Brandon Richards said in a statement, “These losers lost at the ballot box and soon they will also lose in court.”

The legal move against heavily Democratic California marks the first time the Justice Department has sued over a flurry of unusual, mid-decade House map revisions across the country that were drawn to maximize partisan advantage in advance of next year's elections.

Three Republican-led states — Texas, along with Missouri and North Carolina — have not faced federal legal action after revamping district lines following Trump's call for new maps to expand GOP numbers in the House. Civil rights advocates have argued that the new boundaries in Texas and Missouri illegally disadvantage minority communities at the ballot box.

California voters overwhelmingly approved Proposition 50, a constitutional amendment changing the congressional boundaries to give Democrats a shot at winning five seats now held by Republicans in next year's midterm elections.

The Justice Department is joining a case challenging the new map that was brought by the California Republican Party last week. The Trump administration accuses California of racial gerrymandering in violation of the Constitution by using race as a factor to favor Hispanic voters with the new map. It asks a judge to prohibit California from using the new map in any future elections.

“Race cannot be used as a proxy to advance political interests, but that is precisely what the California General Assembly did with Proposition 50 — the recent ballot initiative that junked California’s pre-existing electoral map in favor of a rush-job rejiggering of California’s congressional district lines,” the lawsuit says.

Prop 50 was Newsom's response to Trump’s maneuvers in Texas, where Republicans rejiggered districts in hopes of picking up five seats of their own ahead of the 2026 midterm elections, when House control will be on the line.

Democrats need to gain just a handful of seats next year to take control of the chamber, which would imperil Trump's agenda for the remainder of his term and open the way for congressional investigations into his administration. Republicans hold 219 seats, to Democrats’ 214.

The showdown between the nation’s two most populous states has spread nationally, with Missouri, North Carolina and Ohio adopting new district lines that could provide a partisan advantage. Other states are considering similar moves.

The national implications of California’s ballot measure were clear in both the money it attracted and the high-profile figures who became involved. Tens of millions of dollars flowed into the race, including a $5 million donation to opponents from the Congressional Leadership Fund, the super political action committee tied to House Speaker Mike Johnson, R-La.

Former Republican Gov. Arnold Schwarzenegger opposed it, while former President Barack Obama, a Democrat, appeared in ads supporting it, calling it a “smart” approach to counter Republican moves aimed at safeguarding House control.

The contest provided Newsom with a national platform and he has confirmed he will consider a White House run in 2028.

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Richer reported from Chicago.