The U.S. Supreme Court has ruled that Congressional redistricting maps—including Maryland’s—are none of their business, regardless of partisan gerrymandering complaints.

In a 5-4 decision issued Thursday, the last day of the court’s term before a summer break, Chief Justice John Roberts wrote that the justices have no role to play in what they saw as a political argument that the states should resolve on their own.

The ruling, which also affected cases in other states,  represented a defeat for Gov. Larry Hogan and Maryland Republicans, who had argued the map was purposely drawn to favor Democrats.

Hogan called the decision “terribly disappointing” in a statement and pledged to “vigorously continue this fight, both in Maryland and across our nation.”

He said he would introduce in the next General Assembly session a bill to “put the drawing of districts in the hands of a balanced, fair, and nonpartisan commission—instead of partisan politicians.”

A similar bill died in this year’s session.

Attorney General Brian Frosh, a Democrat who appealed lower court decisions rejecting Maryland’s map, said in a statement this is “a sad day for our democracy.”

“We urged the Supreme Court to adopt a nationwide standard that would prevent extreme partisan gerrymandering,” he said. “The decision today instead prevents voters everywhere from challenging in federal court any redistricting map as excessively partisan.”

He said only Congress has the power to outlaw partisan gerrymandering.

In his opinion, Roberts said drawing districting plans is “highly partisan by any measure,” but argued that the courts are the wrong place to settle those disputes.

Associate Justice Elena Kagan wrote the dissent for the court’s four liberals.

"For the first time ever, this court refuses to remedy a constitutional violation because it thinks the task beyond judicial capabilities," she said.

The decision reverses lower court rulings in Michigan, North Carolina and Ohio as well as Maryland. Federal courts in those states had ordered new maps drawn. It also ends proceedings in Wisconsin, where a retrial was supposed to take place this summer after the Supreme Court last year threw out a decision on procedural grounds.

New maps will be drawn by the legislatures in all 50 states after the 2020 census.

The Associated Press contributed to this report.