Fight over new US House districts in California could turn on advertising edge in closing days

The map pushed by Democratic Gov. Gavin Newsom aims to bolster his party's chances of regaining a House majority in 2026 and counter Republican efforts to add more seats in Texas and other states.

Voting began earlier this month and concludes Nov. 4.

Over 1.5 million Democratic mail ballots have been returned so far, outpacing about 853,000 Republican ballots, though that's not surprising in a state where registered Democrats outnumber GOP voters by nearly 2-to-1.

Data compiled by advertising tracker AdImpact show Democrats and other supporters have nearly $9 million in ad buys booked on broadcast TV, cable and radio. But opponents have virtually no time reserved, though the data don't include some popular streaming services like Hulu and YouTube or mail advertising.

According to AdImpact, supporters have aired nearly $70 million in ads so far, compared to about $31 million from opponents.

The outcome of the fight over so-called Proposition 50 will have national implications. A Democratic House would menace President Donald Trump's agenda for the remainder of his term, while Newsom is widely seen as a likely 2028 presidential contender who would get a publicity boost within his party for spearheading a plan to sidetrack Trump's conservative playbook.

“If we lose this election in California it means Democrats have virtually no chance of taking back the House,” Newsom warned in a recent fundraising pitch to supporters.

Where is the money?

Earlier in the campaign the Congressional Leadership Fund, a super PAC tied to House Speaker Mike Johnson, kicked in a $5 million donation to opponents. But conspicuously, a hoped-for late surge in national Republican dollars has yet to materialize.

Investing in heavily Democratic California is often seen as a dicey bet for GOP donors, and Republicans are fighting across the country to hold their slim majorities in the House and Senate next year. Trump has mostly kept a distance from the contest in a state he lost in landslides in three presidential elections, but where he also has a loyal conservative base and received more votes than any previous Republican presidential candidate.

California is home to some of the nation's most expensive media markets. When it comes to money, it's not just a matter of fighting off Newsom's new House map for the GOP — tens of millions of dollars more will be needed to defend the dwindling number of Republican House incumbents in the state, whether Proposition 50 passes or not.

With the 2026 midterms approaching and House control on the line, national Republican donors “are looking at those dollars and thinking where are they needed the most,“ said Tim Lineberger, who was communications director for Trump’s 2016 campaign in Michigan and also worked in the former president’s administration. With critical House races emerging around the country, those dollars might go elsewhere “rather than fight what might be inevitable here.”

But with millions of Trump voters in California “it's still an important fight to have in this state,” Lineberger added.

Longtime Republican strategist Jon Fleishman, a former executive director of the California Republican Party, asked, “Does the road to the White House or the Senate or the House really run through California?”

“If we are not seeing a lot of national money coming in, we may be getting an unfortunate answer to that question,” Fleishman said.

Will California's maneuvers to counter Trump matter?

How much California's political maneuvering will matter in House control — even if the new map is approved next month — is not yet known.

The proposed California House districts — crafted by Democrats behind closed doors — have been designed to add five Democratic U.S. House seats to offset Trump’s moves in Texas to gain five Republican districts before the 2026 midterm elections. That could boost the Democratic margin to 48 of California’s 52 congressional seats, up from the 43 seats the party now holds.

But Republicans in Missouri, North Carolina and Indiana are making moves that could add GOP House seats as well — districts are crafted state by state. Republicans hold a 219-213 majority in the U.S. House, with three vacancies.

Is it stop Trump, or a Democratic power grab?

The framework of the race is set, with Newsom depicting the contest as a battle against Trump to save democracy, while Republicans and their supporters decry the proposal as a blatant power grab intended to make the state’s dominant Democrats even more powerful while discarding House maps developed by an independent commission.

A handful of Republican congressmen who could see their districts dramatically reshaped have mostly stayed away from the campaign spotlight.

The single largest donor in the campaign could probably walk through downtown Los Angeles in the middle of the day without getting recognized. Charles Munger Jr. — son of the late billionaire Charlie Munger, who helped Warren Buffett build Berkshire Hathaway into an investment powerhouse — has funneled over $30 million into the effort to block Newsom's plan.

Munger, a longtime Republican donor who was instrumental in establishing independent redistricting in the state, says voters need to put aside talk of Trump and look at how Newsom's map would upend representation by carving up districts for political gain.

Voters should ask, “Is this good for you?” Munger told reporters recently. “Do you want to trust these people who drew these maps this way?"

The campaign has lured some marquee names — former Republican Gov. Arnold Schwarzenegger has appeared in ads opposing the change, while former Democratic President Barack Obama has endorsed Newsom's proposal. But without a candidate on the ballot, the race has lacked for gripping drama.

What it takes to win

To surpass the 50% mark and win, Newsom and his supporters are hoping to keep the focus on Trump, with the intent of driving up a large turnout of Democratic and other left-leaning voters. Because Republicans make up only 1-in-4 voters in the state, opponents will need to get a heroic GOP turnout while peeling off a slice of Democrats as well as getting an edge with independent voters.

At a rally last week in suburban Los Angeles opposing the proposal, Republican retiree Anne White lamented that the plan would in some cases create oddly shaped districts that would combine rural and farming areas than tend to lean Republican with liberal coastal cities.

“Those people have nothing in common with one another,” White said. While the current districts were established by an independent commission in public hearings, Newsom “wants to undo all of that.”