On April 7, thousands of Wisconsin citizens braved a global pandemic to show up at the polls to vote. Some commentators blamed Republicans in the legislature for forcing voters to choose between their health and the health of their democracy. Others blamed the Supreme Court for reinforcing this choice, because in Republican National Committee v. Democratic National Committee, the court’s conservative majority reversed an order by federal Judge William Conley that would have made it easier for Wisconsin voters to vote from home.

We agree that a Supreme Court decision led to this situation, but not the decision most are discussing. Our research suggests that the real culprit is the Supreme Court’s 2018 political gerrymandering decision in Rucho v. Common Cause. In that case, the court could have — yet failed to — curb the type of extreme partisanship that led to what happened in Wisconsin. Rucho specifically addressed partisan gerrymandering cases out of North Carolina and Maryland. But in a case decided the year before, the court overturned on technical grounds a federal-district court’s decision that struck down Wisconsin’s state legislative redistricting plan, which had been enacted by the Republican-controlled state legislature.

What happened in Wisconsin and what the Supreme Court said

The Wisconsin Democratic Party, along with a number of other plaintiffs, sued Wisconsin’s election administrators after the state government insisted on holding the election despite the pandemic and a stay-at-home order. A district court judge sided with the plaintiffs, ordering Wisconsin officials to accept ballots even if those ballots were mailed after Election Day, as long as the ballots are received by April 13. The state’s Republican Party appealed. The case made it to the Supreme Court.

In an unsigned opinion, five justices concluded that the district judge exceeded his legal authority. The majority invoked the principle that “lower federal courts should ordinarily not alter the election rules on the eve of an election.” In extending the deadline, the majority concluded that the lower court order “fundamentally alter[ed] the nature of the election.” The majority also argued that the plaintiffs did not ask for the relief that the district court gave them.

The Supreme Court’s refusal to ban partisan gerrymandering in Rucho v. Common Cause

The Wisconsin primary date was so hotly contested in part because its legislature is so overwhelmingly Republican. That’s because in 2010, when the legislature had the once-a-decade obligation to redraw voting districts, the Republican majority drew districts specifically to make it easier for Republicans to win and harder for Democrats. That’s called partisan gerrymandering, something the Supreme Court had an opportunity to rule on in Rucho — and did not. The court justified its Rucho decision by arguing that deciding such claims would make the court seem too partisan. As we wrote before and after the Rucho opinion, the court’s refusal to limit partisanship in drawing voting districts encourages political officials to manipulate voting rules for partisan reasons.

As many political scientists have shown, U.S. politics are extremely partisan and polarized. As a result, many citizens worry that elected officials will game electoral rules, practices and decisions for purely partisan ends. Because electoral rules affect voter turnout, without the threat of judicial supervision, elected officials feel increasingly free to manipulate voting rules in whichever way will give them an advantage in gaining or staying in power. That includes in how they draw voting districts.

Given this, we predicted that the Supreme Court’s decision not to supervise political gerrymandering claims would lead to partisan fights tying up the federal courts, including the Supreme Court — and that as a result the court would be perceived as increasingly and irredeemably political.

Lessons from Wisconsin and Rucho’s unintended consequences

Wisconsin illustrates our prediction about the downstream effects of the Supreme Court’s partisan gerrymandering decision. State officials in Wisconsin could have modified their election regulations to prevent the state’s citizens from having to place their health at risk to cast their ballots. According to news accounts, Republican legislators in Wisconsin refused to postpone the election, as Democratic Gov. Tony Evers ordered, because they believed that low voter turnout would help Republican candidates win. Predictably, the Democrats turned to the federal courts.

It is easy to see this case in partisan terms. In fact, it is described that way in the case’s name: Republican National Committee v. Democratic National Committee. And while the decision was unsigned, the dissenters signed their opinion, making it clear that the decision came from the court’s conservative majority — Chief Justice John G. Roberts Jr. and Justices Clarence Thomas, Neil M. Gorsuch, Samuel A. Alito Jr. and Brett M. Kavanaugh — all who were nominated by Republican presidents. Those five reversed the decision of a federal judge appointed by a Democratic president, ruling in favor of the Republicans. The court’s liberal justices, Justices Ruth Bader Ginsburg, Stephen G. Breyer, Elena Kagan and Sonia Sotomayor, all nominated by Democratic presidents, would have upheld the lower court decision and ruled in favor of the Democrats.

We can expect more such disputes. The court had a chance in Rucho to curb the type of partisanship that led to the Wisconsin case. It will now have to deal with the consequences of that decision.

Guy-Uriel E. Charles (@ProfGuyCharles) is the Edward and Ellen Schwarzman professor of law at Duke Law School.

Luis E. Fuentes-Rohwer (@Prof_lfr) is the Class of 1950 Herman B. Wells endowed professor of law at Indiana University Mauer School of Law.

They are the co-authors of a forthcoming book on voting rights from Cambridge University Press titled “Race, Political Power, and American Democracy: Voting Rights Law and Policy for a Divided America.”