The lawsuit, submitted to the U.S. District Court for the Central District of California, argues that the new maps violate constitutional protections by taking race into account when drawing district boundaries. Republican officials are asking the court to block the maps from being implemented before next year’s elections.

Proposition 50, which passed on Tuesday night, suspends the congressional district maps previously drawn by California’s independent redistricting commission. In their place, the measure installs a new set of political boundaries crafted by Democratic lawmakers and strategists, with the goal of flipping as many as five Republican-held House seats.

The ballot campaign for Proposition 50 was heavily backed by California Governor Gavin Newsom, who framed the measure as a direct response to Republican-led redistricting efforts in states such as Texas, Florida, and Georgia. Those maps were drawn after the 2020 census with the backing of President Trump and state-level GOP lawmakers seeking to secure long-term political advantage.

Democrats in California argued that Republicans in those states had engaged in aggressive gerrymandering — and that California could no longer stand by while its congressional influence was diminished. Newsom described Proposition 50 as a way to “level the playing field” in a national fight over political power.

Republicans, however, say the new maps in California are just as partisan — only benefiting Democrats instead. In their lawsuit, GOP leaders claim that race was used improperly in determining district lines, a legal argument that has frequently appeared in redistricting challenges across the country.

California Republicans attempted to block Proposition 50 before Election Day, but those efforts failed in court. Wednesday’s legal action marks their latest attempt to stop the maps from taking effect before the 2026 midterm elections.

Democratic officials responded to the lawsuit with confidence, saying that the new district borders were developed with electoral fairness in mind and would withstand judicial scrutiny. They emphasized that voters had expressed clear support for the change.

If the maps remain in place, Democrats could see major gains in next year’s House races. Several suburban and coastal districts currently held by Republicans would become more favorable to Democratic candidates, potentially shifting the balance of California’s congressional delegation even further to the left.

The challenge comes at a time when control of the U.S. House of Representatives remains closely contested nationwide. President Trump has made holding the House a key priority heading into the next election cycle, as Republicans seek to maintain legislative power while Democrats try to regain momentum.

For now, the legal fight over California’s districts is expected to move quickly, with both sides acknowledging that any delay could complicate candidate filings, campaign planning, and the broader national map of competitive races.

The outcome of this lawsuit will not only shape California politics — it may influence the next Congress, and potentially the direction of national policy, for years to come.