One of 2025’s major elections could have major reverberations for the 2026 midterms.

Californians are voting on a ballot initiative, “Proposition 50,” to determine if the state will adopt a new congressional map that redraws five districts to be more Democratic-leaning, potentially allowing Democrats to flip them in the midterms.

Supporters of Proposition 50 — including California Gov. Gavin Newsom and former President Barack Obama — have pushed for the new map.

Texas Republicans, encouraged by President Donald Trump, revised their maps in a rare mid-decade redistricting move that could allow Republicans to gain five seats in 2026 — and insulate the GOP from the historic midterm headwinds a president’s party can face.

“We have a chance at least to create a level playing field in the upcoming midterm elections,” Obama said during a recent call with supporters of the campaign to vote “yes”.

Hannah Milgrom, a spokesperson for Yes on 50, the political committee supported by Newsom, told ABC News that the group has been working with over 230 community organizations on the ground. 

National Democrats have largely supported the initiative, hoping it will be the first of other Democratic efforts to push back on Republican-led redistricting in Texas, Missouri, and other states. 

But Rep. Kevin Kiley, a California Republican whose district would be reshaped and made significantly more Democratic-leaning, told ABC News partisan gerrymandering is a “plague on democracy,” and has unsuccessfully pushed House Speaker Mike Johnson to take up a bill banning the practice.

“I think it takes power away from voters, undermines the fairness of elections and degrades representative government,” he said. 

Spokespeople for two of the political committees opposing Proposition 50, which are supported by megadonor Charles T. Munger Jr. and former Speaker of the House Kevin McCarthy, respectively, told ABC News they were focused in the final weeks before the election on reaching persuadable voters and to emphasizing arguments about allowing voters to choose their politicians, not the other way around.

Actor and former governor of California Arnold Schwarzenegger, who supported independent redistricting as governor, has also spoken out against the proposition. He said in September, “If you vote yes on that, you’re going backwards.”

“Prop 50 will have a big impact on the midterms … the U.S. House margin right now is so narrow that every seat in every state could make a difference for which party controls Congress,” Christian Grose, a professor of political science at the University of Southern California, told ABC News. 

If the proposition passes, Grose added, a large margin of support could signal to Democratic donors that there’s enthusiasm for the party — and could impact whether other blue or red states decide to redraw their congressional maps as well.

Grose said Democrats are likely more fired up in part because campaigning towards Democratic voters is how to win with ballot propositions in California, Grose said, but also because of what they see as national stakes: “Democrats, maybe nationally, are viewing things as an existential threat; are viewing Trump as an existential threat. So anything that pushes back against Trump, anything that helps Democrats, is resonating.”

ABC News’ Brittany Shepherd contributed to this report.