The Florida Legislature gave final approval on Wednesday to an aggressive new map of the state’s congressional districts sought by Gov. Ron DeSantis, a Republican. The map could give his party as many as four new seats, improving its chances of keeping control of Congress in the November midterm elections.
The votes happened hours after the Supreme Court issued a long-awaited decision on the landmark 1965 Voting Rights Act, weakening the law. Mr. DeSantis, predicting such an outcome in recent months, used it as the main justification to redraw the state’s map, despite little interest from state lawmakers in doing so.
The redrawn districts would eliminate four Democratic-held seats — one in the Tampa area, one in the Orlando area, and two in the Fort Lauderdale area — effectively slashing the number of Democratic-leaning seats in half. Florida has 28 congressional districts; seven are held by Democrats after an eighth Democrat resigned last week.
Democrats have decried the mid-decade redistricting as a power grab by Republicans doing the bidding of President Trump, who faces sagging polling numbers as the midterms approach.
Several voting rights groups plan to challenge the map in court once Mr. DeSantis signs it into law. Their arguments are likely to center on a provision in the Florida Constitution that effectively bans partisan gerrymandering.
The Supreme Court decision found that Louisiana lawmakers had unconstitutionally relied on race when they drew a 2024 congressional map to create a majority-Black district. The decision came as Florida lawmakers were discussing the proposed map in Tallahassee. State senators took an hourlong break to read the decision. State representatives raced to vote, with the tally ending up 83-28 along party lines, Republicans in favor and Democrats against. Republicans hold supermajorities in the State House and Senate.
As the vote began, State Representative Angie Nixon, a Jacksonville Democrat who is running for U.S. Senate, protested on the House floor.
“It is out of order!” she yelled through a bullhorn. “You are violating the Constitution!”
State senators later approved the map 21-17, mostly along party lines, though four Republicans voted against it.
One of them, State Senator Jennifer Bradley of Fleming Island, south of Jacksonville, had said on Tuesday that she could not accept a central argument from the governor’s office: that the map no longer needed to comply with the state’s ban on partisan gerrymandering.
“I can’t do it,” Ms. Bradley said of supporting the map. “It’s just unconstitutional.”
The Florida Constitution effectively bans partisan gerrymandering under the Fair Districts amendments, which voters passed in 2010. But lawyers for Mr. DeSantis said that the state no longer needs to comply with those amendments, citing a Florida Supreme Court ruling last year.
In that ruling, the conservative-leaning court found that using race as a consideration in drawing maps under Fair Districts violated constitutional equal protection guarantees. The governor’s lawyers argued this week that because the court invalidated the race provision of Fair Districts, then all of its provisions, including the one banning partisan gerrymandering, should be rendered moot.
Nikki Fried, the chairwoman of the Florida Democratic Party, called that argument “asinine.” The court, she said in an interview, had a chance to overturn all of Fair Districts but chose not to do so.
Mr. DeSantis has appointed six of the seven justices on the Florida Supreme Court.
The governor called state lawmakers into a special redistricting session this week but did not release his proposed map until Monday, a day before the session began. That gave lawmakers extraordinarily little time to consider the map. A typical redistricting process involves months of extensive hearings and many possible maps, including some drawn by lawmakers.
On Tuesday, in committee hearings filled by dozens of voters who opposed the map, lawmakers grilled Jason Poreda, the top DeSantis aide who drew it.
He said he had started working on the map two weeks ago and did not finish until this past weekend. Mr. Poreda also acknowledged that the partisan breakdown of congressional districts was one of the factors that he considered in drawing the new map.
“Not using race, and not having to adhere to the Fair Districts Amendment, the entire suite of redistricting criteria that are available to other states I used here, including partisan data,” he said.
He called the map “race neutral,” a characterization that Democrats rejected. They pointed to how Black and Puerto Rican communities would be split into more than one district in several parts of the state, diluting their political power.
Since the map was released, congressional candidates have been declaring which new district they intend to run for. Florida holds its primaries in August.
Republican state lawmakers chose not to participate in the debate about the map before Wednesday’s votes. The Republican state senator who sponsored the bill, Don Gaetz of Crestview, in the Panhandle, said he disagreed with the governor’s aides that the ban on partisan gerrymandering should not apply, but put forward the map anyway.
Mr. Gaetz insisted that elections are unpredictable and that the map might not result in gains for his party.
“I am not persuaded that this map is necessarily beneficial to the Republican Party,” he said.
Nick Corasaniti contributed reporting from New York.