A coast-to-coast sprint of partisan one-upmanship in which eight states have redrawn their congressional districts since last summer is likely to escalate next year to at least a dozen more as both parties seek maximum advantage in their battle for control of the House.

Four states are considering drawing new congressional or judicial maps for partisan gain in the coming weeks that could be implemented in time for the fall midterms. But the real flurry could come next year, when at least a dozen more that sat out this year’s redistricting parade could join the fray.

The longstanding tradition of drawing political lines only once a decade, after each census, is giving way to an era of perpetual redistricting where officials seek opportunities for partisan gerrymandering at every chance they can. Both parties have ratcheted up their efforts in recent days, assessing every corner of the electoral map for new openings and redoubling their efforts to win control of state capitols, where the power to draw congressional boundaries often lies.

The States Project, which invests in Democratic legislative races, has targeted six states — Wisconsin, Minnesota, Nebraska, Pennsylvania, Oregon and Washington — where gains in state legislatures would protect or add as many as nine congressional seats for the 2028 cycle, according to a memo the group shared with The New York Times. Democrats are also aiming to put more redistricting referendums on ballots in blue states.

“We were very limited in our ability to respond in this cycle because of constitutional constraints that exist in many Democratic-held states across the country,” Representative Hakeem Jeffries of New York, the House minority leader, said in an interview on Friday. “In the next cycle, we will have several of those constraints removed in ways that will allow us to respond in an even more decisive and forceful fashion in advance of 2028.”

The most recent redistricting flurry began in late April, when the Supreme Court declared Louisiana’s House map an unconstitutional racial gerrymander, prompting that Republican-led state and a few others to explore redistricting efforts that align with President Trump’s vision of an aggressive cartographic push to retain power in the House.

Then, on Friday, the Virginia Supreme Court struck down that state’s Democratic gerrymander, which voters had approved in a referendum on April 21. The ruling sparked a resolve among Democrats to be even more aggressive in planning a raft of future gerrymanders that won’t affect the midterm landscape but could help the party in 2028.

Following the Supreme Court’s ruling, Republicans across the South wasted little time trying to eliminate red-state Democratic congressional seats in time for this year’s midterm elections. Tennessee has already passed a new map eliminating the lone Democratic district in the state. Louisiana delayed its primary to pass new maps that would eliminate at least one Democrat-leaning district there. Alabama is also fighting for a different map.

On Thursday, the lower chamber of the South Carolina legislature voted to consider redistricting and introduced a map that would eliminate the only Democratic district in the state, that of Representative James E. Clyburn, who has held it for three decades. The State Senate has yet to vote on either measure.

The rapid escalation of Republican-led redistricting across the South has both unnerved and enraged Democrats. In several of those states, the party is seeking relief in court, but it has otherwise exhausted its redistricting options this year. Next year, however, Democratic officials said they plan to be every bit as ruthless with the maps they control as they say Republicans have been in this cycle.

“It’s a total reshift to the way congressional maps will be drawn in this country, and we should all acknowledge that now,” said John Bisognano, the president of the National Democratic Redistricting Committee. “It could be a monumental change between 2026 and 2028.”

Central to both parties’ battle plans for the next phase of the redistricting wars will be building and maintaining the trifectas — total control of both chambers of a state legislature plus the governor’s mansion — that are needed to enact partisan maps. This increased focus on state capitols will dramatically increase the stakes for usually sleepy legislative elections across the country.

“Anyone who spent a second considering this decision knows it supercharges the power of states, and anyone who’s surprised has been living in a cave,” said Daniel Squadron, a co-founder of the States Project. “We can’t stop the fallout by crossing our fingers and going back to court. We have to win power in state legislatures in November, full stop.”

Democrats hope a wave of backlash to Mr. Trump and his policies will win them full control of state governments in Minnesota, Pennsylvania and Wisconsin. They expect to place a redistricting measure on the ballot this fall in Colorado, while the governors of Illinois, Maryland, New York and New Jersey have suggested they may try (or try again) to join the map-drawing fray next year.

No longer will states wait for new census data each decade to redraw their maps. Now, they plan to take every opportunity to eke out partisan advantage ahead of an election. And after the Supreme Court’s ruling, which weakened a key tenet of the Voting Rights Act that historically had been used to protect minority representation, they are doing so with few legal guardrails in place to limit even the most brazen partisan gerrymandering.

Perhaps no state holds greater potential for a dramatic partisan swing in its congressional map than Wisconsin, a perpetual battleground state where Democrats are now eagerly eying the prospect of flipping a 6-to-2 Republican map on its head in time for 2028.

“Tempering our ambitions is not something we here at the Democratic Party of Wisconsin are known for,” said Devin Remiker, the state party chairman, who believes a 6-2 Democratic map is doable. “Aim for the stars, land in the clouds.”

A constellation of Democratic groups will gather this month to plan strategy and determine targets for this November’s state legislative elections.

Leading the effort is House Majority PAC, the main House Democratic super PAC. The committee’s president, Mike Smith, said Democratic organizations still believe their party will take control of the House, even with the Republican gerrymanders. Their hope, he said, is to create congressional maps that will allow them to hold that majority through the 2028 and 2030 elections.

“We are exploring every avenue to counter the Republican assault on voters across the South,” Mr. Smith said. Plans include investing in Pennsylvania, Washington and Oregon, “where winning additional seats in state legislatures can give us the opportunity to aggressively redraw those maps,” he said.

The Democratic Legislative Campaign Committee, which announced a $50 million budget for 2026, had similarly factored a likely Supreme Court decision on redistricting in a strategy memo released in December. The group is targeting more than 650 seats and aiming to make gains in 42 chambers this year — a reflection of how the Supreme Court case shifted its focus from 2030 and decennial redistricting to an annual battle.

“We have to think about the power every single election cycle because Pandora’s box has been opened, and it seemingly does not have a cap,” said Heather Williams, the president of the D.L.C.C.

Sensing a flood of money into state legislatures from Democrats, the Republican State Leadership Committee has been raising the alarm to donors since April. Edith Jorge-Tuñón, the president of the R.S.L.C, wrote in an internal memo last month that the group was “facing a political environment that is likely to be one of the most challenging for state Republicans in recent years.”

Republicans, she wrote, will largely be defending Republican majorities in Wisconsin, Arizona, Texas and New Hampshire. They’ll also look to regain a supermajority in North Carolina and win total control of split delegations in Wisconsin, Michigan and Pennsylvania.

“The right needs to wake up,” said Mason Di Palma, a spokesman for the R.S.L.C. “If we don’t invest in state legislatures right now, come January of 2029 the House will automatically be controlled by Democrats, even if President Trump’s successor is a Republican.”

Both Democrats and Republicans are also turning to state judicial races, especially elections for state supreme courts, which will play a powerful role in refereeing new maps.

On Thursday, former President Barack Obama endorsed two Democratic candidates for the state Supreme Court in Georgia. Republicans in Utah are working to protect two incumbents.

“I always think that Republicans should be more offensive minded when it comes to judicial races,,” said Adam Kincaid, the executive director of the National Republican Redistricting Trust.

As they tried to do in Virginia this year, Democrats will need to dismantle independent redistricting commissions in some states where they hope to make new maps. New York and Colorado have already begun the process to work around commissions in their states. New Jersey, Washington and Oregon will need near-universal Democratic support in their legislatures to dismantle their commissions and draw new maps.