On Tuesday, Chief Justice John G. Roberts Jr. at one point seemed to agree. “It was preliminary, as opposed to permanent,” he said of the court-drawn maps.

In 2013, the Texas Legislature decided not to draw new maps and instead mostly adopted the one drawn by the court in San Antonio. Scott A. Keller, Texas’ solicitor general, said state lawmakers had adopted the maps after substantial debate and deliberation.

“There is absolutely no evidence in plaintiffs’ briefs that somehow the Legislature was trying to lock in discriminatory districts,” he said.

Allison J. Riggs, a lawyer for the challengers, disagreed. The question for the justices, she said, was, “Did the Legislature adopt the interim plan for race-neutral reasons, or did it use the adoption of that interim plan as a mask for the discriminatory intent that had manifested itself just two years ago?”

Later in the argument, she answered her own question. “They wanted to end the litigation,” she said, “by maintaining the discrimination against black and Latino voters, muffling their growing political voice in a state where black and Latino voters’ population is exploding.”

After three election cycles that used the interim maps it had drawn, the district court ruled that they were flawed. “Although this court had ‘approved’ the maps for use as interim maps, given the severe time constraints it was operating under at the time of their adoption,” the court said that approval was “not based on a full examination of the record or the governing law” and was “subject to revision.”