The national battle to control the U.S. House shifts to California on Tuesday as voters consider a Democratic proposal that could erase as many as five Republican districts and blunt President Donald Trump’s moves to safeguard his party’s lock on Washington power.

The outcome will reverberate into next year’s midterm elections and beyond, with Democrats hoping a victory will set the stage for the party to regain control of the House in 2026. A shift in the majority would imperil Trump’s agenda for the remainder of his term at a time of deep partisan divisions over immigration, health care and the future direction of the nation.

“God help us if we lose in California,” Democratic Gov. Gavin Newsom says.

Democrats need to gain just three seats in the 2026 elections to take control of the House.

Heavily Democratic California and its 52 congressional districts represent by far the Democrats’ best opportunity in an unprecedented state-by-state redistricting battle, which started when Texas Republicans heeded Trump’s demand that they redraw their boundaries to help the GOP retain its House majority. Democrats hold 43 of the state’s seats and hope to boost that to 48.

Trump is fighting not just the Democrats but history. Midterm elections typically punish the party in the White House, but four GOP-led states so far have adopted new district maps to pack more Republican voters into key districts.

Measure supported by Newsom, Obama

California’s Proposition 50 asks voters to suspend House maps drawn by an independent commission and replace them with rejiggered districts adopted by the Democratic-controlled Legislature. Those new districts would be in place for the 2026, 2028 and 2030 elections.

The recast districts aim to dilute Republican voters’ power, in one case by uniting rural, conservative-leaning parts of far northern California with Marin County, a famously liberal coastal stronghold across the Golden Gate Bridge from San Francisco.

The measure has been spearheaded by Newsom, who has thrown the weight of his political operation behind it in a major test of his mettle ahead of a potential 2028 presidential campaign. Former President Barack Obama has urged voters to pass it as well.

Newsom has sought to nationalize the campaign, depicting the proposal as a counterweight to all things Trump.

“Republicans want to steal enough seats in Congress to rig the next election and wield unchecked power for two more years,” Obama says in one ad. “You can stop Republicans in their tracks.”

Critics say two wrongs don’t make a right. They urge Californians to reject what they call a Democratic power grab, even if they have misgivings about Trump’s moves in Republican-led states.

Among the most prominent critics is Arnold Schwarzenegger, the movie star and former Republican governor who pushed for the creation of the independent commission, which voters approved in 2008 and 2010. It makes no sense to fight Trump by becoming him, Schwarzenegger said in September, arguing that the proposal would “take the power away from the people.”

“I don’t want Newsom to have control,” said Rebecca Fleshman, a 63-year-old retired medical assistant from Norco in Southern California, who voted against the measure. “I don’t want the state to be blue. I want it to be red.”

After an early burst of TV advertising, opponents of the plan have struggled to raise cash in a state with some of the nation’s most expensive media markets. Data compiled by advertising tracker AdImpact last week showed Democrats and other supporters with over $5 million in ad buys booked on broadcast TV, cable and radio. But opponents had virtually no time reserved, though the data didn’t include some popular streaming services like Hulu and YouTube or mail advertising.