The United States Supreme Court on Monday unanimously affirmed a lower court’s decision not to issue a preliminary injunction in Benisek v. Lamone, a case centered around whether redistricting in Maryland’s sixth congressional district violated the United States Constitution.

While the high court held that the plaintiffs waited too long to challenge the validity of the congressional map and that an injunction could have a disruptive effect on the electoral process, it did not opine on one central question: Can a redistricting plan be so partisan that it violates the United States Constitution? In the past, the court has struck down districts drawn along racial lines, but it has never struck down an election district on the grounds that it was unfairly partisan.

Redistricting is the means by which new congressional and state legislative district boundaries are drawn. Each of Maryland’s eight United States Representatives and state legislators is elected from political divisions known as districts. District lines are redrawn every 10 years, in accordance with the United States Census. The federal government mandates that districts must have nearly equal populations and must not discriminate on the basis of race or ethnicity.

In Maryland, the General Assembly has primary authority to draw both congressional and state legislative district lines. The governor, aided by an advisory commission, submits a state legislative redistricting proposal. The legislature may pass its own plan by joint resolution, which is not subject to gubernatorial veto. If the legislature fails to approve its own plan, the governor’s plan takes effect. Congressional lines are drawn solely by the legislature and may be vetoed by the governor.

Plaintiffs filed a complaint in the United States District Court of Maryland in 2013, crying foul over the redistricting of the sixth congressional district by the Maryland General Assembly following the 2010 Census. In the complaint, plaintiffs argued the district plan was a partisan gerrymander — voting districts that are redrawn to benefit one political party over another in elections —  which violated the right to representation guaranteed by Article 1 Section 2 of the United States Constitution, and the First Amendment’s protection of political association.

A district judge dismissed the case in 2014. The United States Court of Appeals for the Fourth Circuit affirmed the lower court’s decision, and the plaintiffs appealed to the United States Supreme Court. The Supreme Court’s ruling means the case can continue in the lower courts.

There is currently no law against gerrymandering, and courts have traditionally struggled with the issue, as Bruce DePuyt writes for Maryland Matters:

While critics of gerrymandering contend that tortured line-drawing is easy to spot and an affront to democracy, courts have long struggled with the practical question of determining when a disputed map becomes too political — and how to remedy the situation when that occurs.

Reform advocates tried to accentuate the positive from the Supreme Court’s decision.

“The court kicked this down the road, but states should not,” said Walter K. Olson, a senior fellow at the Cato Institute’s Robert A. Levy Center for Constitutional Studies and co-chairman of the Maryland Redistricting Reform Commission, which Hogan formed to explore taking the map-making process away from politicians. “Instead of [expressing] disappointment, I would stress the positive. … The public has been learning more about this process. The public cares more. This makes a good occasion to once again get back to work on making sure that this issue is heard in state legislatures.”

While the Supreme Court ultimately passed on deciding whether or not partisan-gerrymandering violates the United States Constitution, several other gerrymandering cases are winding their way through the courts — including Rucho v. Common Cause, a North Carolina partisan-gerrymandering case also on the court’s docket — meaning the issue is almost certain to be back before the nation’s high court in the very near future.

The Court came to a similar unanimous ruling on Monday in a second case, from Wisconsin, Gill v. Whitford.