WASHINGTON (Reuters) – Accusations that state legislators drew electoral maps for partisan advantage in violation of the U.S. Constitution will once again come before the U.S. Supreme Court, which agreed on Friday to decide cases from North Carolina and Maryland that could have enduring political consequences nationwide.

The high court has struggled to resolve the legality of the practice called partisan gerrymandering in which boundaries of legislative districts are delineated with the aim of tightening one party’s grip on power.

The justices in June 2018 failed to issue definitive rulings in cases from Wisconsin and Maryland that election reformers had hoped would prompt the high court to impose limits on partisan gerrymandering.

The court will hear oral arguments in both cases in March, with rulings due by the end of June.

In the North Carolina case being taken up by the justices, Democratic voters accused North Carolina’s Republican-led legislature of drawing U.S. House of Representatives districts in a way that disadvantaged Democratic candidates in violation of the constitutional guarantee of equal protection under the law. A lower court sided with the Democratic voters.

In the Maryland case, Republican voters accused Democratic legislators of violating their constitutional free speech rights by redrawing boundaries of one particular U.S. House district to hinder Republican chances of winning. The Supreme Court in June sidestepped a ruling on the merits of the case and a three-judge panel threw out the district in November.