U.S. President Donald Trump’s emergency appeal aimed at limiting the use of mail ballots is poised to test a controversial, 20-year-old Supreme Court principle that was intended to avoid chaos before elections. The “Purcell principle,” rooted in a 2006 Supreme Court decision, warns federal courts against making last-minute changes to voting rules. But the principle has never before been weighed in a Supreme Court case involving a federal election policy like Trump’s effort to give the US Postal Service and the Department of Homeland Security a hand in screening state voter rolls for potential non-citizen voters. How the 6-3 conservative majority deals with its self-created and oft-criticized rule in the Trump case could have practical implications for how the court handles the flood of litigation that will inevitably crash onto its docket this fall, and ahead of the 2028 presidential election. “Here we have potential federal agency action that could impact the way the 2026 election is run,” said Chad Ennis, the vice president of the Honest Elections Project, a conservative group focused on voting policies. “I think this is a novel set of facts and how SCOTUS would apply Purcell, if at all, is an open question.” Signed in March, the president’s executive order would require states to submit lists of eligible voters to the U.S. Postal Service, which would be barred from sending ballots to anyone not on those lists. It would also require states to use tracking barcodes on ballot envelopes. And it would “prioritize” federal prosecution of state election officials who send or receive ballots to non-citizens or others ineligible to vote. The order also requires DHS to create lists of what it views as eligible, US citizen voters in each state. Federal courts in Boston blocked the order’s implementation. Trump filed an emergency appeal at the Supreme Court last week. That appeal doesn’t deal with the merits of the president’s order, nor does it say anything about Purcell. But if the court sides with Trump on any portion of the case, it will likely set up a showdown over the doctrine later this year. A group of Democratic states challenging Trump will respond to the president’s emergency appeal on Monday. The Supreme Court could then rule later this month. Avoiding chaos? Because of the Purcell doctrine, timing almost always lurks as a central issue in federal challenges to voting rules. In December, the Supreme Court allowed Texas to use a congressional map that boosted the GOP’s chances of keeping control of the House, partly because the primary election was set for March. In 2024, the court cited Purcell when it allowed Louisiana to use a congressional map that benefited Democrats because the state argued that candidate filing deadlines were fast approaching. Two years earlier, roughly a month out from Alabama’s primary election, the court appeared to rely on Purcell to keep a congressional map drawn by the state’s Republicans in place, despite a lower court decision that the map diluted the political power of Black voters. The court’s brief order didn’t cite Purcell, but Justice Brett Kavanaugh wrote a lengthy concurrence defending its application in that case. “This court has repeatedly stated that federal courts ordinarily should not enjoin a state’s election laws in the period close to an election,” Kavanaugh wrote. “That principle — known as the Purcell principle — reflects a bedrock tenet of election law: When an election is close at hand, the rules of the road must be clear and settled.” Critics, however, note that a majority of the court was fine allowing Louisiana to revert immediately to a Republican-friendly congressional map in May even though absentee voting had already started for the primary under a different map that included a second Black-majority district. Justice Ketanji Brown Jackson, a liberal, questioned at the time how her colleagues could square the hurry-up approach in that case with its reticence to engage at the last minute in others. Jackson noted that the emergency Louisiana appeal came “in the midst of an ongoing statewide election.” “The court unshackles itself from both constraints today and dives into the fray,” she wrote. “And just like that, those principles give way to power.” Her dissent drew a sharp rebuke from Justice Samuel Alito, a conservative, who noted that the map Jackson would have left in place for this year’s election had been ruled unconstitutional by the Supreme Court days earlier. The state had also suspended voting in the House contests after the Supreme Court’s ruling in Louisiana v. Callais. Purcell is not currently at issue in the Trump appeal over the mail ballots, but the states are likely to ask the court to keep the doctrine in mind to head off a catch-22 scenario. That’s because Trump’s central argument is that the states and groups who are challenging his order sued too soon. If the Supreme Court agrees with Trump, then the states will have to wait to revive their litigation. And that will necessarily push the cases closer to the November election, allowing the administration to raise Purcell to bar courts from weighing in. Trump’s Justice Department has argued that the lawsuit against the administration isn’t “ripe” because the government hasn’t taken any steps yet to enforce its order. “The executive order is an intra-branch directive from the president to his subordinates — which, of its own force, does not change anything at all about elections in any state,” US Solicitor General D. John Sauer told the justices in the administration’s appeal last week. At the same time, the administration hasn’t ruled out trying to invoke Purcell at a later stage in the case. At a May hearing in a separate case dealing with the same executive order, US District Judge Carl Nichols, a Trump nominee, asked if the administration would try to raise that argument. The administration’s attorney, Stephen Pezzi, said he didn’t think it was likely. But he also didn’t rule it out. “I, of course, can’t and won’t take an argument off the table about what the world will look like in August from the lectern today,” Pezzi said. “But it’s far from clear to me that that sort of consideration would apply here.” Novel questions Because the federal government has historically had an infinitesimal role in running elections, the last-minute voting cases that race up to the Supreme Court have dealt with state policies. Sophia Lin Lakin, director of the Voting Rights Project at the American Civil Liberties Union, described the Trump administration’s executive order on mail ballots as unprecedented. And that means the case may shed light on the court’s approach to Purcell. “Many of these decisions on Purcell have been handled on the shadow docket in a way that hasn’t necessarily garnered clear support of five justices, so we’ve been at times piecing together different ideas along the way to determine how it might play out,” said Lakin, whose group is challenging Trump’s executive order in a separate case pending in a federal court in Massachusetts. While Trump’s emergency appeal raises questions the court hasn’t directly addressed, Lakin said she believes there are clues that a majority of justices might vote to intervene to halt the administration’s order, even with Purcell on their minds. Increasingly, the court’s conservatives have framed the principle as a check on the power of federal courts to interfere in elections that are run by states. In that sense, the doctrine is partly about ceding control to run elections to the states — not the federal courts, nor federal agencies. “This mail voting executive order sits on the wrong side of the line,” Lakin said. “It’s a federal actor imposing late-breaking changes on state election systems over the objections of the states that run them.” Derek Muller, a law professor at Notre Dame who is an expert on election law, agreed. “Purcell has more weight when you are enjoining a state rule because of federalism concerns,” Muller said. “That on its own is a powerful distinction” from a federal election policy. The court also considers more than just Purcell when it’s weighing an elections case, Muller said. Those other factors, he said, might disfavor the federal government if courts felt it was attempting to game the system with last-minute changes. “I also think Purcell doesn’t really work when the rule is being enacted very close in time to the election,” Muller said. “In that circumstance, regular equitable considerations would allow courts to intervene.” A federal appeals court in Washington, D.C., okayed Trump’s executive order in a separate case last week. In the final paragraph of that order, the court dismissed the idea that the Trump administration would be able to invoke Purcell to shut down a future challenge to its order later this year. “Plaintiffs’ fear has the Purcell principle backwards,” the panel of three appeals court judges said. If the administration were to attempt to impose “massive changes on the states’ voting systems on the threshold of the upcoming election,” then federal courts could block that — despite Purcell — because such a move would “preserve the states’ existing electoral status quo.” The appeals court, tellingly, didn’t cite a single Supreme Court decision to back up that conclusion.
