A view of the Maryland State House in Annapolis. (Patrick Semansky/AP)

Federal judges on Thursday declined to throw out Maryland’s congressional voting map that challengers say was intentionally designed to give Democrats an electoral edge.

The 2-to-1 decision allows the state to maintain those voting boundaries for the 2018 election and puts the lawsuit on hold until after the Supreme Court has ruled in a similar partisan gerrymandering case from Wisconsin scheduled for October.

The challenge in Maryland centers on the 6th Congressional District in Western Maryland that was redrawn to include parts of heavily Democratic Montgomery County. The plaintiffs say the state’s Democratic leaders violated their First Amendment rights by diluting the number of Republican voters and ensuring that a Democrat would win.

All three judges on the panel at a July hearing acknowledged plaintiffs had presented convincing evidence that the state’s Democratic leaders intended to make it easier for their party to pick up another congressional seat. But in their split decision, the judges said it was not enough to warrant the “highly consequential” preliminary injunction the challengers sought.

Attorney Michael B. Kimberly, who represents a number of Maryland Republicans, said Thursday he would appeal the ruling to the Supreme Court.

In the 24-page opinion, U.S. District Judges James K. Bredar and George L. Russell rejected the request to immediately scrap the state’s electoral map because the judges said it would “cause an unprecedented disruption in Maryland’s legislative and districting process.”

“The time and resources necessary to implement a new map would surely have the effect of scuttling other legislative priorities in advance of the 2018 session,” the court said, adding that it also was “not yet persuaded that it was the gerrymander (versus a host of forces present in every election) that flipped the Sixth District.”

Long held by Republican Roscoe Bartlett, the 6th District seat changed hands after the new lines were drawn in 2011 and has since been filled by Democratic Rep. John Delaney.

In his dissent Thursday, Judge Paul V. Niemeyer said he would have required state lawmakers to redraw congressional boundaries without using information about how Maryland residents had voted in the past.

Niemeyer, who sits on the Richmond-based U.S. Court of Appeals for the 4th Circuit, said the majority “overlooks the obvious.”

“The record could not be clearer that the mapmakers specifically intended to dilute the effectiveness of Republican voters in the Sixth Congressional District and that the actual dilution that they accomplished was caused by their intent.”

Even as they disagreed on Thursday, all three judges took aim at political gerrymandering, alternately referring to the practice as “cancerous,” “noxious” and destructive to representative democracy.

The office of Maryland Attorney General Brian Frosh, who is defending the voting map, had asked the three-judge panel to put the case on hold pending a ruling in the Supreme Court’s Wisconsin case.

The high court has routinely struck down redistricting plans that reduced the influence of racial minorities. But the Supreme Court has long been more tolerant of partisan gerrymandering, in part because the justices have never agreed on a clear standard for determining when such ma­nipu­la­tion violates voters’ constitutional rights.

If the Maryland challengers appeal Thursday’s ruling as expected, the Supreme Court must either affirm, reverse or accept the case for oral arguments. The justices could also pause the challenge while the Wisconsin case proceeds.

Assistant Attorney General Sarah W. Rice argued during the hearing last month that forcing the state to redraw its voting boundaries before the 2018 election would confuse voters and place current candidates “under a cloud” of uncertainty as they continue their campaigns.

Government lawyers also said in court papers that challengers “failed to explain how they were harmed in any way different from the injury suffered by every other Maryland voter who was disappointed with the outcome of the 2012 election in his or her district.”

During the hearing, Kimberly displayed photos and videotaped depositions of top Democratic officials, including Senate President Thomas V. “Mike” Miller Jr., House Speaker Michael E. Busch and former governor Martin O’Malley. The former governor said he believed in 2011 that he should wield his power to favor Democrats, but he has since called for redistricting reform.

Miller and Busch, in their depositions, said partisan factors were not a strong consideration for them during the redistricting process, and that they were largely unfamiliar with data their staffs received at the time showing the likelihood of Democratic victories under various configurations.