Tennessee Republicans on Wednesday proposed a congressional map aimed at diluting the state’s lone majority-Black district, a swift response to last week’s Supreme Court ruling that weakened a landmark voting rights law.

The new map slices Memphis, a majority-Black city, and Shelby County into three districts and likely will give Republicans the ability to flip Tennessee’s lone remaining Democratic seat, which includes the city.

Democratic lawmakers, whose opposition means little under a Republican supermajority in the state’s General Assembly, and Black leaders across Tennessee have compared the effort to carve up the Ninth Congressional District to Jim Crow-era voter suppression tactics. They have accused conservatives of a power grab that undermines Black voters in Memphis, who have long favored Democrats.

Republicans, cheered on by President Trump, have rejected those claims. Instead, they have said, they are responding to the Supreme Court ruling, which raised the bar for what constitutes a racial gerrymander under the Voting Rights Act of 1965.

Tennessee joins a series of states that have engaged in tit-for-tat redistricting battles since last summer, when Mr. Trump called for Republican-led states to redraw their maps and Texas became the first. Since then, new maps have materialized in half a dozen states controlled by both Republicans and Democrats, with more on the horizon, in the fight for Congress in November’s elections. Tennessee’s new map, if passed, would be the first directly responding to the high court ruling.

Under the map, Shelby County — which includes Memphis — is split into three districts. One district now runs along the state’s western border before extending down to include part of Williamson County, a suburban county just outside Nashville. Two other districts now share part of Shelby County and more rural, conservative communities in Tennessee.

“The Supreme Court has opined that redistricting, like the judicial system, should be colorblind — the decision indicated states like Tennessee can redistrict based on partisan politics,” Speaker Cameron Sexton said in a statement. “Tennessee’s redistricting will reduce the risk of future legal challenges while promoting sound and strategic conservatism.”

The General Assembly is expected to vote as soon as Thursday.

The Supreme Court struck down a Louisiana congressional map that included two majority-Black districts, arguing that it violated the Constitution by using race as the primary factor in redistricting. The ruling has set off a scramble across Southern states with Republican leadership, all of which have at least one majority-Black district, before the 2026 midterms.

Louisiana last week delayed its House primaries — though thousands of absentee votes had already been cast — to allow its Legislature to draft a new map. The South Carolina legislature is also facing conservative pressure to quickly adopt a new congressional map.

Alabama is barred by court order from adopting a new map until after the 2030 census but is trying to get the order lifted. In anticipation of a favorable ruling, lawmakers convened a special session this week with the goal of allowing the state to delay certain House primaries.

In Florida, debate over a new map that could give Republicans up to four new seats was underway as the Supreme Court ruling became public.

Mr. Trump spoke directly to Gov. Bill Lee of Tennessee, a Republican, to press for a new map the day after the ruling, and top Tennessee Republicans have raced to ease the way for rapid passage.

To do so, the legislature must first repeal a state law banning redistricting between census years each decade.

Hundreds of protesters gathered outside the State Capitol on Tuesday to voice opposition to a new map. Once inside, their chants and boos reverberated around the halls of the building. (On Tuesday, the House approved a strict rules package, which bans anyone removed from the gallery or committees for disorderly conduct from returning for the remainder of the session.)

“History will not look back kindly on you when you had an opportunity to do what was right and you chose to do something else,” said State Senator Raumesh Akbari, a Memphis Democrat, who delivered an emotional plea to Republican colleagues on Tuesday.

The Ninth Congressional District seat is currently held by Representative Steve Cohen, a white Democrat who has repeatedly maintained the support of many Black voters since he first won the seat in 2007. He is facing a Black primary challenger, State Representative Justin J. Pearson; both men joined a rally against the new map on Tuesday.

The new map is likely to scramble existing congressional races, including the one between Mr. Cohen and Mr. Pearson. Under the proposed map, the proposed Ninth Congressional District would stretch much farther east along the Tennessee border with Mississippi.

It was not immediately clear whether every Republican would support the map, but given the party’s supermajority, some amount of defection will not matter.

The map also affects Middle Tennessee, where the legislature had already split the Democratic stronghold of Nashville among three Republican-leaning districts. The Fifth Congressional District, which is currently held by Representative Andy Ogles, a Republican, no longer contains parts of Davidson County, which encompasses Nashville.

Should a new map be passed and signed into law, a legal challenge is expected. The primary in Tennessee is currently scheduled for Aug. 6.

Leanne Abraham and Katherine Chui contributed reporting.

President Trump promised political payback last year when Indiana state senators from his own party voted down his plan to redraw the state’s congressional map to help Republicans.

On Tuesday, he got much of what he wanted, as at least five of the seven anti-redistricting Republicans facing Trump-backed challengers lost their primaries, according to The Associated Press. The results reflected Mr. Trump’s continuing sway over Republican voters and his ability to enforce political consequences for Republican officeholders who defy him.

In the other races, at least one incumbent won his primary and another race remained too close to call.

State legislative primaries are often low-drama affairs, but Mr. Trump’s involvement brought unusual levels of attention and outside spending. The president issued social media endorsements to the seven challengers and hosted some of them at the White House, while outside groups aligned with Mr. Trump poured money into the races.

As the challengers emphasized their ties to Mr. Trump, many of the incumbents focused on their own conservative credentials, as well as endorsements from groups supporting farmers, gun rights or abortion restrictions.

Rather than a contest between moderates and conservatives, the primaries became a test of how much deference Republicans owe Mr. Trump and how much control the president holds over rank-and-file voters.

“It’s not that anyone is less or more pro-life,” said Lt. Gov. Micah Beckwith, a Republican redistricting supporter who backed most of the Trump-endorsed challengers. “It’s really that, do you understand the battle we are in, and do you understand the role Indiana plays in that battle on a national stage?”

State Senator Spencer Deery, one of the anti-redistricting incumbents, described the election as a test of how much sway Washington policymakers and their allies have over state policymaking.

“What’s at stake,” he said, “is the question of whether state legislators are going to be free to listen to their constituents and to govern their state without the outside meddling of enormous financial sums of dark money.”

On Tuesday, voters had diverging views of the political landscape and of the president’s endorsement.

In Granger, Ind., along the Michigan border, Tony Xouris said redistricting was his top issue and that he turned out to vote for the Trump-backed challenger to Senator Linda Rogers, who voted against the redrawn map.

“She lost my vote,” said Mr. Xouris, a semiretired insurance agent. “She’s a RINO. She’s a bad Republican.”

But outside the polls in Schererville, Ind., near Chicago, Matt Bartz said he was voting for Senator Dan Dernulc even though Mr. Trump had endorsed a challenger.

“I’m a Trump supporter,” said Mr. Bartz, a retired steelworker. “I was under the understanding that he wanted states to regulate themselves, take care of themselves, but now he’s coming back with this revenge type of thing and I’m not happy with that.”

The races also split political leaders in Indiana, where Republicans have amassed power over the last 20 years, but where there are longstanding fissures between the party establishment and an ascendant movement that hews closely to Mr. Trump.

Gov. Mike Braun and Mr. Beckwith, along with some members of the congressional delegation, came out in support of many of the challengers.

On the other side, former Gov. Mitch Daniels, who helped usher in Indiana’s era of Republican dominance, became a leading voice against redistricting. His successor as governor, former Vice President Mike Pence, endorsed one of the incumbents seeking re-election.

The rupture began last year when Mr. Trump was pushing redistricting nationwide in a bid to gain seats in Congress in the midterm elections. Several Republican-led states quickly fell in line, and some Democratic-led ones moved to counter with their own maps. But a critical mass of Indiana lawmakers remained opposed to the plan to draw a map that would position Republicans to flip the state’s two U.S. House seats held by Democrats.

When lawmakers returned to Indianapolis in December, the Republican-led House approved a new map. But the Republican-controlled Senate said no, with a slim majority of Republicans joining Democrats to vote the bill down even as Mr. Trump threatened political consequences.

“Any Republican that votes against this important redistricting, potentially having an impact on America itself, should be PRIMARIED,” Mr. Trump wrote in a November social media post that referred to two senators as Republicans in name only.

He soon followed through on that promise, endorsing challengers to seven of the eight anti-redistricting Republicans who ran for re-election this year. Other Republicans who voted against the bill have two years remaining in their terms or did not run for re-election.

Kim Bellware, Robert Chiarito and Nick Corasaniti contributed reporting.