A panel of federal judges in San Antonio on Monday will begin hearing arguments in a lawsuit challenging Texas’s congressional district lines in one of the most consequential legal debates over the way legislators draw political boundaries.

The case is the latest in a litigation battle that has raged since 2011, when civil rights groups sued, claiming Texas district lines illegally discriminated against minorities. Texas legislators adopted new maps in 2013, drawn by a federal court, and now those maps are coming under scrutiny.

The three-judge panel that will hear arguments in the case beginning Monday said earlier this year that the state legislature had improperly, and intentionally, diluted the political power of minority voters in three of those districts. The judges also ruled that several state House districts violated minorities’ civil rights.

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The civil rights groups who sued over the court-drawn 2013 maps say they were meant to be temporary. They have asked the court to force new changes to the district lines ahead of the 2018 elections.

Texas’s current district lines overwhelmingly favor Republicans: The GOP owns 95 of the 150 seats in the state House, 25 of 36 congressional seats and 20 of 31 state Senate seats.

The changes civil rights groups seek would not shift the balance of power, given the size of the Republican majorities.

But the ultimate goal is to force Texas to return to a system under which the federal Justice Department would have to approve any district lines written by the legislature, both now and after the 2020 Census — giving Democrats a significant stake in the debate over new district lines.

That system, called preclearance, evaporated when the Supreme Court struck down part of the Voting Rights Act, freeing Texas and other states from the burden of seeking federal permission to change state lines.

The court will not decide whether to place Texas back under preclearance during the trial this week. But if the three judges decide to strike down some Texas state House district lines, it would set up another legal battle down the road.

The Texas case is one of a handful of redistricting battles taking place across the country and making their way toward the Supreme Court.

Justices next term will hear legal arguments over a case out of Wisconsin, where plaintiffs accuse state legislative Republicans of improperly discriminating against Democratic voters when they drew their maps the last time around. A similar case out of North Carolina is working its way through the legal system, too.