A federal judge blocks Louisiana’s congressional map, calling it a racial gerrymander.

A federal judge ruled on Monday that Louisiana’s new congressional map represented a racial gerrymander and must be redrawn to include a second district that gives Black voters the chance to elect a candidate of their choice.

The judge, Shelly D. Dick of the United States District Court for the Middle District of Louisiana, ordered the State Legislature to produce a revised map of the state’s six congressional districts by June 20. She also directed the state to extend the filing deadline for House candidates, now set for June 22, to July 8.

Her 150-page ruling said the House map enacted by the Republican-controlled Legislature illegally packed Black voters into the Second Congressional District, then split the remaining Black voters among the remaining five districts.

Civil rights groups argued that the Legislature could easily have created a second majority-Black congressional district, but chose instead to effectively duplicate the single predominantly Black district that was in the preceding House map.

That district, which is roughly 70 percent Black, snakes along the Mississippi River from Baton Rouge to New Orleans. Much of it is surrounded by the Sixth District, which is one-third Black.

Roughly a third of the state’s population is African American — one of the largest shares of any state — while 57 percent of the state’s residents are white. The 2020 census showed that the state’s Black population had grown by 3.8 percent in the preceding decade, while the white population had declined by 6.3 percent.

Judge Dick’s opinion took pains to argue that her order gave more than enough time for the state to draw a new map and still hold primary elections, which take place on Nov. 8. The general election is in December.

The Supreme Court has overruled a number of court decisions making changes in elections in the last two years, citing a legal doctrine called the Purcell principle that says courts should not make changes in laws or rules too close to an election lest they confuse voters.

Most notably, the court in February reinstated an Alabama congressional map that a lower court had struck down as diluting the voting power of Black people, saying it would hear an appeal of the ruling after the November election.

Courts have yet to say how soon before an election day is too soon to override voting procedures, but Judge Dick, who was named to the bench by President Barack Obama, argued forcefully that the principle did not apply in the Louisiana case.

The state’s attorney general had said that an order to redraw maps would “act like a hurricane” on the state election schedule, but the judge said state officials themselves had testified that mechanics like reprinting ballots and telling voters which district they lived in, while inconvenient, were far from impossible to carry out.

“Placing a bureaucratic strain on a state agency in order to rectify a violation of federal law is not analogous to a natural disaster,” she wrote. “Protecting voting rights is quite clearly in the public interest, while allowing elections to proceed under a map that violates federal law most certainly is not.”

Black state legislators had argued for a second district in redistricting hearings last fall, with Ted James, at the time a state representative who led the Legislative Black Caucus, saying flatly that “one-third of six is two.”

Gov. John Bel Edwards of Louisiana, a Democrat, had vetoed the Legislature’s House map in March, saying it was “simply not fair to the people of Louisiana and does not meet the standards set forth in the federal Voting Rights Act.”