Late in 2016, a federal district court struck down Wisconsin’s Republican-drawn state Assembly map as an unconstitutional partisan gerrymander. On Friday, the court followed up that decision by ordering the legislature to craft new districts for the 2018 elections by Nov. 1. Of course, those same lawmakers were responsible for creating the very maps that were struck down in the first place, so it remains to be seen how the court will treat any remedial plans that legislators come up with, but this latest ruling represents progress in a case that’s crucial for redistricting reform.

Wisconsin is one of the most gerrymandered states in the country: Democrats won the statewide popular vote for the Assembly in 2012, but the GOP’s maps helped them maintain their majority. New maps could upend that. But even more importantly, this ruling might also have much broader implications, because a likely appeal to the Supreme Court could set the stage for a national precedent constraining partisan gerrymandering.

An earlier Supreme Court ruling called Vieth v. Jubelirer previously held that partisan gerrymandering could be unconstitutional. But in that case, Justice Anthony Kennedy, as the deciding vote, refused to strike down the particular map in question for lack of a manageable standard to determine when impermissible partisan gerrymandering takes place.

The plaintiffs in Wisconsin, however, have sought to overcome that problem by proposing one such standard called the “efficiency gap” that would examine how many votes get “wasted” in each election. Under this test, if one party routinely wins landslide victories in a few seats while the other party wins much more modest yet secure margins in the vast majority of districts, it could signify a gerrymander that has gone so far as to infringe upon the rights of voters to free speech and equal protection.

While the federal district court didn’t rely solely on the plaintiffs’ “efficiency gap” in reaching its decision, the opinion appears to have been precisely designed with Kennedy’s Vieth ruling in mind. Should plaintiffs ultimately succeed in persuading the Supreme Court’s perennial swing justice to finally set forth a standard to judge when partisan gerrymandering crosses the line, courts could begin striking down redistricting plans across the nation and at all levels. Republicans have gerrymandered 55 percent of congressional districts and most state legislatures nationwide, so such a decision could have extremely far-reaching consequences.