A sharply divided Supreme Court ruled Thursday that federal courts can’t rein in politicians who draw political maps to entrench a partisan advantage, a decision that will influence the redrawing of congressional districts after the 2020 census.

In a 5-4 opinion, the court’s conservative wing found the Constitution did not give the courts the authority to strike down maps as partisan gerrymanders. Instead, the majority wrote, that is a political question and a task for Congress and the states.

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The ruling pointed to legislative efforts, including a bill from House Democrats that would require independent commissions to oversee redistricting in each state, as well as the handful of states where voters did the same through ballot initiatives.

“We express no view on any of these pending proposals,” Chief Justice John G. Roberts Jr. wrote for the court. “We simply note that the avenue for reform established by the Framers, and used by Congress in the past, remains open.”

The decision keeps the current congressional maps in North Carolina and Maryland, which were at issue in the cases. It dooms similar partisan gerrymandering challenges in Ohio and Michigan, where lower federal court judges had ordered new congressional districts.

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The ruling comes just ahead of the 2020 census and the ensuing redistricting process based on the census results that states use to draw congressional maps — which in turn will affect the partisan makeup of the House and potentially which party is in control of the chamber.

Critics say Thursday’s decision gives a green light to state officials and lawmakers to carve up their states in a way that strips voters of the ability to choose who represents them in Congress or the statehouse.

Justice Elena Kagan, in a passionate dissent, wrote that the majority “goes tragically wrong” in giving a pass for judicial review to the “worst-of-the-worst cases” of partisan gerrymandering, and “the chances for legislative reform are slight.”

Majority Leader Mitch McConnell, R-Ky., has no intention of allowing a Senate vote on the House bill, calling it “a naked attempt to change the rules of American politics to benefit one party.”

“Of all the times to abandon the Court’s duty to declare the law, this was not the one,” Kagan wrote.

In the North Carolina case, state Republican lawmakers required that map to entrench a 10-3 advantage for their party despite a majority of voters statewide voting for Democratic candidates. In the Maryland case, state officials said they redrew the map to increase the Democratic advantage in the congressional delegation from 6-2 to 7-1.

The majority said the Supreme Court does not have a directive to allocate political power or influence with legislative maps, and there are no legal standards to guide them for when an inherently political redistricting process is too political.

Roberts wrote that none of the tests proposed by the challengers or the dissenting justices meet that need.

“The expansion of judicial authority would not be into just any area of controversy, but into one of the most intensely partisan aspects of American political life,” Roberts wrote. “That intervention would be unlimited in scope and duration — it would recur over and over again around the country with each new round of redistricting, for state as well as federal representatives.”

Kagan countered that lower courts have coalesced around standards for determining when a political map has too much politics, and checking these gerrymanders “is not beyond the courts.”

“The practices challenged in these cases imperil our system of government,” Kagan wrote. “Part of the Court’s role in that system is to defend its foundations. None is more important than free and fair elections.”

The ruling will also put more pressure on congressional and state lawmakers to pass reforms, said Michael Li, senior counsel for the democracy program at the Brennan Center for Justice.

“The public is aware of this issue in a way that they have never been aware of this issue,” he said. “While this could occur in the dark in the past, I think people are going to be watching very closely now, because there is a distrust of the political class.”

House Democrats’ signature campaign finance and election overhaul bill would institute independent redistricting commissions to draw congressional districts to curb partisan gerrymandering, a method that has been adopted by a growing number of states.