On Wednesday night, the Pennsylvania Supreme Court finally released its majority opinion explaining why Republicans’ gerrymander of Pennsylvania’s congressional districts violates the state constitution. (On Jan. 22, the court had issued a brief order directing the Legislature to redraw the illegal districts without fully explaining its reasoning.) Justice Debra McCloskey Todd’s 139-page opinion for the court is thorough and persuasive—and, critically, its reasoning isn’t entirely limited to Pennsylvania. Instead, Todd illustrates how dozens of other state constitutions may be interpreted to protect voting rights more robustly than the U.S. Constitution does. Her decision will arm activists in every state with a powerful new tool in the fight against political redistricting.

The U.S. Supreme Court will soon decide whether partisan gerrymandering runs afoul of the First and 14th amendments. But, as Todd explained, the Pennsylvania Supreme Court had no obligation to wait for SCOTUS’ decision in Gill v. Whitford, because the Pennsylvania Constitution provides rights independent from the U.S. Constitution. Specifically, the state constitution—which actually predates its federal counterpart—declares that all elections “shall be free and equal.”

Nearly 150 years ago, the Pennsylvania Supreme Court ruled that this provision requires all votes to be “equally potent” in any election. In 1914, the court reiterated that this clause guarantees that “every voter has the same right as every other voter,” and “each voter under the law has the right to cast his ballot and have it honestly counted.” And in 1986, the court clarified that any law that “dilutes the vote of any segment of the constituency” infringes upon the Free and Equal Elections Clause.

In 2018, then, the question for the court was whether political redistricting—drawing congressional lines to entrench a certain party’s electoral power—impermissibly dilutes certain voters’ ballots. Todd easily concluded that it did. “Partisan gerrymandering,” she explained, “dilutes the votes of those who in prior elections voted for the party not in power to give the party in power a lasting electoral advantage.” She continued:

By placing voters preferring one party’s candidates in districts where their votes are wasted on candidates likely to lose (cracking), or by placing such voters in districts where their votes are cast for candidates destined to win (packing), the non-favored party’s votes are diluted. It is axiomatic that a diluted vote is not an equal vote, as all voters do not have an equal opportunity to translate their votes into representation. This is the antithesis of a healthy representative democracy. Indeed, for our form of government to operate as intended, each and every Pennsylvania voter must have the same free and equal opportunity to select his or her representatives.

Pennsylvania provides a stark example of this phenomenon. Democrats and Republicans have received roughly the same number of votes in the past three House elections—that is, since the current gerrymander took effect. Republicans have seized 13 House seats in each election. Democrats have taken just five.

To remedy the problem, Todd looked to the traditional, neutral criteria that the framers of the Pennsylvania Constitution used to draw districts. Those map-makers placed a high value on “geographical continuity,” minimizing the division of municipalities and counties between districts. Partisan map-makers, by contrast, largely ignored such continuity in gerrymandering the state. (Before 1992, no municipalities in Pennsylvania were divided among multiple districts; the current map divides 68 municipalities among two or more districts.) Todd pointed to Pennsylvania’s notorious 7th Congressional District—a “Rorschachian” sprawl that hinges, ludicrously, around a restaurant called Creed’s Seafood & Steaks—by way of example. The Washington Post’s Christopher Ingraham has mapped the evolution of this mangled district:

The evolution of Pennsylvania's 7th congressional district, from 1953 to today https://t.co/A3n0Iklmq8 pic.twitter.com/xUwwwUnsly — Christopher Ingraham (@_cingraham) February 8, 2018

The court ordered the Legislature to draw new districts “composed of compact and contiguous territory” that do not unnecessarily divide any municipalities or counties. If the Legislature and the governor cannot agree on a new, nonpartisan map by Thursday, the court will commission one itself for use in the 2018 midterms.

The right to vote may be understood to encompass the right to vote in a genuinely competitive district.

By its own terms, the court’s decision applies exclusively to Pennsylvania. But in a lengthy footnote, Todd notes that 12 other state constitutions include a Free and Equal Elections Clause identical to Pennsylvania’s. Courts in at least three of these states—Delaware, Illinois, and Kentucky—have already interpreted this clause to provide “an equal right to each citizen, on par with every other citizen, to elect their representatives.” None of these states’ supreme courts have yet considered a gerrymandering-related claim under their state constitution. But if they do, Todd suggested, they may well find that no election that takes place under a gerrymandered map is truly “free and equal.”

Todd needn’t have stopped there. As University of Kentucky College of Law professor Joshua Douglas has noted, virtually every state constitution protects voting rights more explicitly than the U.S. Constitution does. In addition to the 13 states that require elections to be “free and equal,” an additional 13 require elections to be “free and open,” a similar command that has been interpreted identically. Forty-nine states expressly protect the right to vote (unlike the federal Constitution). Only Arizona’s constitution does not guarantee that right—but it does contain a Free and Equal Elections Clause, which the state Supreme Court has interpreted to protect voting rights. Moreover, most state constitutions lay out guidelines for the redistricting process, and none consider partisan advantage to be the kind of legitimate criteria that legislatures can use to draw maps.

State courts have occasionally invoked these provisions to strike down burdens on the franchise, such as voter ID laws. The Pennsylvania Supreme Court’s ruling raises the possibility that they might also be used to combat partisan gerrymandering. Perry Grossman, senior staff attorney at the New York Civil Liberty Union’s Voting Rights Project (and an occasional Slate contributor), told me that “the right to vote is more than just the right to cast a ballot. It’s the right to cast an effective ballot.” Grossman said that “broad, strong language about the right to vote” contained in so many state constitutions “offers a sharper sword” against many types of disenfranchisement, “including vote dilution as well as vote denial.” Put differently, the right to vote may be understood to encompass the right to vote in a genuinely competitive district.

Some voting rights advocates have worried that federal courts might stymie such efforts by invoking the federal Constitution’s Elections Clause, which grants certain redistricting powers to state legislatures. Indeed, Pennsylvania Republicans brought this exact claim in their emergency appeal to the U.S. Supreme Court. But on Monday, Justice Samuel Alito rejected that emergency appeal without comment. It appears likely, then, that SCOTUS will stay out of gerrymandering disputes between legislatures and state courts—giving those courts an opportunity to reinvigorate state-based protections against partisan redistricting.

Of course, the U.S. Supreme Court’s impending decision in Gill v. Whitford looms over the Pennsylvania battle. And it is possible that SCOTUS could prohibit partisan gerrymandering altogether. But it appears much more likely that the justices will limit only truly extreme political redistricting, leaving leeway for legislators to draw districts that still disfavor the minority party. If that happens, advocates across the country should finish the work of Gill by challenging partisan gerrymanders under their states’ constitutions. Not every state supreme court is as progressive as Pennsylvania’s, but plenty are sufficiently nonpartisan to grasp the threat that gerrymandering poses to democracy. Judges in every state have the power to push back against the illegitimate entrenchment of political power through redistricting. Pennsylvania just showed them how to use that power.