An election law case currently before the U.S. Supreme Court may reshape American elections, energizing election integrity advocates but disappointing Democrat-aligned activists. At the heart of the dispute is the definition of the term “election day,” as used in federal statute. In particular, the case centers on whether or not ballots cast by mail can be counted after Election Day has concluded, provided that they were postmarked before the conclusion of Election Day.

The case began in January of 2024. President Donald Trump was still former President Donald Trump and, as he campaigned for the Republican presidential nomination, the specter of the 2020 election loomed large, with its partisan polarization. For months, even years after former Vice President Joe Biden was declared the winner of the 2020 election, as several states and counties were still counting ballots, Trump supporters and a broad swath of Republicans leveled accusations of widespread election fraud. In many cases, late ballots were the lynchpin of those fraud allegations. The theory was that partisan election officials and election activists (such as ballot harvesters) would find or deliver fresh batches of ballots, nearly all of which would be marked in Biden’s favor, even days after the election. So long as they were postmarked prior to the end of Election Day, they would be counted.

The Republican National Committee (RNC) and Mississippi Republican Party filed a lawsuit in January of 2024, challenging the Magnolia State’s laws allowing election officials to continue counting mail-in ballots even after Election Day, provided that those ballots were postmarked before Election Day’s conclusion. Judge Louis Guirola, Jr. of the U.S. District Court for the Southern District of Mississippi rejected the challenge, finding in favor of Mississippi’s election officials, but a three-judge panel of the U.S. Court of Appeals for the Fifth Circuit largely disagreed with the ruling, reversing in part and vacating in part.

“Congress statutorily designated a singular ‘day for the election’ of members of Congress and the appointment of presidential electors. Text, precedent, and historical practice confirm this ‘day for the election’ is the day by which ballots must be both cast by voters and received by state officials,” wrote Judge Andrew Oldham in his opinion, joined by Judges Kyle Duncan and James Ho, all three Trump appointees. Because Mississippi allowed ballots to be counted that were received up to five days past Election Day, the judges determined that Mississippi’s law was preempted by federal law. The appellate court refused a petition from Mississippi to re-hear the case en banc, but the Supreme Court accepted the state’s petition.

On Monday, Supreme Court justices heard oral arguments in the case, Watson v. RNC, and a majority indicated that they are likely to agree with the Fifth Circuit judges and the RNC: “Election Day” means Election Day, and ballots must be received by officials before the end of Election Day. As has become custom, Justice Clarence Thomas, the court’s longest-serving member, was the first to pose questions, focusing on when someone votes — is it when the ballot is cast, or when the ballot is received? “If I give my ballot, mail-in ballot, to my neighbor, is that a choice?” Thomas asked Scott Stewart, Mississippi’s solicitor general, who was advocating in favor of the state’s election laws. “When do I know whether or not a choice is final?” Thomas continued. “I made a final choice when I handed it to my neighbor.” Stewart contended that the choice is only final once it has been submitted to election officials; in other words, ballots must be marked and submitted to a carrier of some variety prior to Election Day, but may still be received and counted by election officials in the days following Election Day.

Justice Amy Coney Barrett took up Thomas’s line of questioning. “I don’t understand why Mississippi’s definition in the next case would preclude a state from adopting a law along the lines of the one that Justice Thomas is proposing,” Barrett began. She suggested a hypothetical scenario in which a voter entrusts their ballot to a neighbor, who has volunteered to deliver neighbors’ ballots for them. “What if the state said that’s fine; if you’ve cast your final vote and you’ve designated someone to carry your vote … as long as it gets to the ballot box five days after Election Day, it’s fine. Why does your definition preclude what Justice Thomas hypothesized?” She pointed out that neither postal workers nor neighbors are election officials, asking why a ballot should count as cast if entrusted to a postal worker, but not if entrusted to a family member or neighbor. “Your definition didn’t say final as submitted to an impartial third party or final as submitted to a common carrier. You said the final choice has been made. And there are lots of different ways, it seems to me, that you could make a final choice.”

The next to probe the hypothetical was Justice Neil Gorsuch. “What if a state came up with a law that said so long as a notary — that’s official, that’s recognized, certified that you cast your ballot on Election Day, and it was delivered later by whatever means, common carrier or not, what in your theory of the preemptive effect of this statute would preclude that law?” he asked. Gorsuch further hammered at the question, asking Stewart to define clearly when a ballot is cast. The justice suggested that he himself could notarize an affidavit attesting that a hypothetical voter had filled out his ballot and handed it to a Supreme Court justice prior to the election. “Even if it’s notarized, an affidavit, it was final on the day of, and somebody brings it in to the state offices a week or three months later, that doesn’t count, but if it goes into the mail, it does? What in the statute, what words in the statute would you have us read that into, that rule into?”

“That’s good enough under your theory. It has to be, I think. And if that’s okay, why can’t a state say: How about a time-stamped video showing that I voted on Election Day? Here I am filling out my ballot, and then my brother or maybe some aggregator of ballots brings it in a week or three later,” Gorsuch suggested. “Well, the state says that’s official, the state says that’s fine, ballot aggregators are great, and so long as it’s a time-stamped video or a notary or maybe a Supreme Court, or who knows what, the librarian says you cast it on the day of the election, we’re good, we’re good to go, right?” When Stewart suggested that a ballot should count as having been cast once deposited in the mail, Gorsuch fired back, “FedEx isn’t an election official.”

Justice Samuel Alito addressed a different “line” connected to the heart of the question, asking how many days after Election Day a state may be permitted to receive and count ballots purportedly mailed by or on Election Day. “Isn’t it the case that some state allows — will count ballots that are received 21 days after Election Day?” he asked. “Is that okay? Is that alright?” Stewart suggested that counting ballots received up to three weeks after Election Day would not be in conflict with federal statute. “So there’s no limit?” Alito responded. “Except I suppose the day when the presidential electors have to be appointed or the day when the next Congress begins, starts its session, that’s the only limit on counting mail-in ballots.”

Stewart argued that historical precedent is on Mississippi’s side, pointing to examples like Civil War soldiers being given a grace period for ballots that must be mailed to their home states in the mid-1800s. All that matters, he contended, is that citizens cast their votes by the same date across the nation; federal statute does not dictate that those ballots all be received or counted by the same date. Alito took issue with the assertion. “We don’t have Election Day anymore. We have election month, or we have election months,” Alito observed, in what may have been a swipe at many blue states’ lengthy early voting periods. “I mean, the early voting can start a month before the election. The ballots can be received a month after the election.”

Justice Brett Kavanaugh also waded into the fray, expressing some skepticism towards Mississippi’s election administration. He noted that the grace period afforded for mail-in ballots is not a long-standing tradition in the state, but a relatively novel introduction to accommodate voters during the COVID-19 era. The justice also plumbed the question of perceived fraud. “The longer after Election Day any significant changes to totals take place, the greater the risk that the losing side will cry that the election has been stolen,” he said, citing an argument by New York University Law Professor Richard Pildes. Addressing Stewart, he asked, “One: Is that a real concern? Two: Does that factor into how we think about how to resolve the scant text and maybe conflicting, or evolving, history here?”

Over the course of the Supreme Court’s questioning of Stewart’s arguments on behalf of Mississippi, Justices Thomas, Alito, and Gorsuch all but confirmed that they would decide against Mississippi’s election administration law, while Kavanaugh and Barrett gave less-strong indications that they would likely agree that federal statute preempts Mississippi’s law, though Barrett was the less certain of the two. The only other Republican-appointed justice, Chief Justice John Roberts, asked almost no questions of Stewart.

Next up, Paul D. Clement, a seasoned and respected attorney arguing on behalf of Mississippi’s Libertarian Party and the RNC against counting ballots received after Election Day, relied heavily on historical precedent, including Civil War and World War II absentee voting practices, when military officers were deputized to serve as election officials and ballots had to be received by those officials by Election Day, not days afterward. Early voting was explored during Clement’s arguments: Justice Elena Kagan suggested that the arguments proffered by Clement and the RNC would seemingly bar early voting; Clement responded that, according to federal statutes, the election must be “consummated” by Election Day, but added that others have advanced a “pretty good argument that early voting is problematic.” Kagan didn’t let the comment slide. “Every time you try to state what your rule is, it seems to me it’s a rule that prevents early voting,” she said. “You’re basically saying there are two things that have to happen, and they have to happen on Election Day, and it’s the casting of the vote and the receipt of the vote.”

Like Kavanaugh, Clement also addressed the public’s confidence in the integrity of elections, arguing that federal statute established a uniform, nationwide Election Day largely in order to allay public concerns over ballot-box-stuffing — concerns which he said are just as valid and prevalent today as in the 19th century. The attorney suggested that, in elections where a large number of ballots were received and counted after Election Day ended, whoever lost the election was unlikely to concede that he had lost fair and square, due to the potential for fraud. Concerns over fraud and public trust prompted Congress to enact federal election statutes in the first place, Clement contended.

Barrett returned to the question of early voting, suggesting that if the arguments advanced by Clement and the RNC were followed to their natural conclusions, then early voting would also likely be preempted by federal statute. Acknowledging that many states do not allow the counting of ballots received after Election Day, she nonetheless stressed that the administration of elections is left almost entirely up to the states, asking if there is “any reason to think that these laws were adopted because of a concern about preemption by federal law, as opposed to just: this is a really good policy?”

The Trump administration also weighed in on the case, with U.S. Solicitor General D. John Sauer briefly arguing before the court. “Defining election as merely private choice alone would authorize statutes where the voters mark their ballots and give them to a private party such as a ballot harvester or a party operative or even hand them in three weeks later and just say or attest that they made the decision on Election Day,” he stated, referring to state laws allowing ballots to be received and counted days or weeks after Election Day as “so general and permissive that [they] would authorize statutes that Congress could not possibly have approved in the 19th century.” He added, “Official receipt is at the definitional heart of election.”

The Supreme Court’s decision in the case would have a significant impact across the nation. At least 14 states (including Mississippi) and Washington, D.C. allow ballots received after Election Day (but postmarked on or before the day) to be counted, while 17 additional states allow ballots from U.S. citizens overseas and from military voters to be received and counted after Election Day.

Justices Kagan, Sonia Sotomayor, and Ketanji Brown Jackson are expected to side with Mississippi, while Justices Thomas, Alito, Gorsuch, and Kavanaugh indicated that they would more than likely side with the RNC’s arguments. Roberts, typically a swing vote between the court’s conservative-leaning and more liberal-leaning wings, gave no indication which way he might decide in the end, while Barrett tempered what seemed early on like a willingness to accept the RNC’s arguments, ultimately giving no clear indication which way she might decide.