WASHINGTON — Congressional redistricting battles launched in the middle of the decade have moved 34.8 million Americans into new U.S. House districts, or roughly one in 10 people nationwide, according to a Protect Democracy analysis released this week. The study also found that about one-fifth of Americans now live in districts where more than 25% of voters are new compared with the 2024 election cycle. That level of turnover can change the political makeup of a district even when its boundaries appear only modestly different. The unusual redistricting push began after President Donald Trump urged Texas lawmakers to redraw the state’s congressional map to improve Republican prospects. The effort prompted California to respond with a referendum-backed map designed to benefit Democrats. Other states followed, turning redistricting into a national partisan contest outside the usual post-census schedule. Republicans could gain as many as nine House seats through the new maps, according to the analysis. The changes have increasingly prioritized partisan advantage over geographic continuity and keeping shared communities together, researchers said. “If this trend continues, it really brings into question whether or not elected officials are really representing their constituents anymore, or if the voters are being randomly picked by mapmakers to squeeze out partisan advantage,” said Ben Raderstorf, a Protect Democracy policy advocate and co-author of the report. The consequences are already visible in states where voters are trying to determine which district — and which candidates — will appear on their ballots. In Missouri, conflicting court decisions created uncertainty over new districts supported by Trump. The U.S. Supreme Court last week blocked the new boundaries from being used in the general election, requiring the state to return to its previous map after the new districts had been used for the primary. Protect Democracy warned that frequent partisan remapping could reduce public confidence in elections and make it harder for voters to hold lawmakers accountable. Safe districts can shield incumbents from shifts in public opinion, while rapidly changing boundaries may make it more difficult for candidates, organizers and residents to build lasting relationships. The report described a potential “doom loop” in which each party responds to the other’s redistricting efforts with more aggressive mapmaking. That cycle could deepen the country’s political polarization and further weaken the connection between lawmakers and the communities they represent. Nine states currently use nonpartisan commissions to draw congressional boundaries, although those systems have limits. California, for example, temporarily set aside its commission-drawn map after voters approved a new plan in response to Texas’ actions. The report’s authors called for broader structural changes, including proportional representation or an agreement between the parties to use nonpartisan districting plans. Such reforms would face significant resistance in Congress and state legislatures. “This is only going to get worse until somebody stops it,” Raderstorf said. “The logic of gerrymandering points inevitably towards maximalist partisan advantage on both sides. There is no off-ramp other than reform. It is the only way to break the cycle.”