The plan worked. In 2016, Republican congressional candidates won 53 percent of the statewide vote. But, as predicted, they again won in 10 of the 13 congressional districts, or 77 percent of them.
In 2018, the statewide vote was about evenly divided, but Democrats again secured only three seats.
The case, Rucho v. Common Cause, No. 18-422, was an appeal from a decision in August by a three-judge panel of a Federal District Court in North Carolina. The ruling found that Republican legislators there had violated the Constitution by drawing the districts to hurt the electoral chances of Democratic candidates.
The Maryland case, Lamone v. Benisek, No. 18-726, was brought by Republican voters who said Democratic state lawmakers had in 2011 redrawn a district to retaliate against citizens who supported its longtime incumbent, Representative Roscoe G. Bartlett, a Republican. That retaliation, the plaintiffs said, violated the First Amendment by diluting their voting power.
Mr. Bartlett had won his 2010 race by a margin of 28 percentage points. In 2012, he lost to Representative John Delaney, a Democrat, by a 21-point margin.
Last year, after the Supreme Court returned the case to the United States District Court in Maryland, a three-judge panel of that court ruled for the challengers, barred state officials from conducting further congressional elections using the 2011 maps and ordered them to draw new ones.
The Supreme Court addressed partisan gerrymandering last term, too, while Justice Anthony M. Kennedy was still on the court. Justice Kennedy, in his questions last term and in a 2004 concurring opinion, left the door open to the possibility that some kinds of political gamesmanship may be too extreme.