The Bost v. Illinois State Board of Elections Supreme Court Case Explained

Lis Frost, J.D. ’07, explains the Bost v. Illinois State Board of Elections Supreme Court case and its potential implications for mail‑in ballot rules and future elections.

It’s been more than 200 years since states first formally authorized voting by mail in the United States. The first such law, adopted by Pennsylvania in 1813, allowed soldiers serving in the War of 1812 to cast absentee ballots from the field. Since then, mail-in balloting has expanded so that every state now allows some form of voting by mail. In the 2024 election alone, nearly 50 million Americans took part in the election by mailing in their ballots.

Earlier this year, the Supreme Court handed down a decision in Bost v. Illinois State Board of Elections that could facilitate more election‑related litigation over how mail-in ballots are counted, particularly rules that allow ballots received after Election Day to be tallied. Congressman Mike Bost, a longtime representative from Illinois’s 12th congressional district, claimed Illinois’s practice of allowing ballots postmarked by Election Day to be counted if they are received within 14 days after the election caused him harm.

Lis Frost, J.D. ’07, who represented the Democratic Party of Illinois in an amicus brief filing when the case reached the Court of Appeals for the Seventh Circuit, takes us inside the case, showing why it matters beyond Illinois, including the implications it might have for politicians, voters and future elections.

Read the Transcript

Lis Frost (LS): My name is Lis frost, and I am the litigation chair at Elias Law Group, and I'm also an alumna of the University of Washington’s law school.

UW Law: What is Illinois doing that some candidates object to?

LS: So, Illinois is doing something, actually, that many, many states and U.S. territories do and have done for decades. It is allowing its election officials to count ballots that are cast by election day but are received in the mail sometime afterward. And specifically, these laws vary from state to state. The Illinois law said that as long as a ballot is postmarked by election day, if it is received by election officials within sometime in the two weeks thereafter, it will be counted. So, to be clear, and I think this is a really important point, these are ballots that are cast by valid voters. They are ballots that are cast in accordance with state law, and the issue is whether or not they should be thrown in the trash and their ballots not counted in the ultimate count for the candidate, or if they should, in fact, be counted. The postmark ensures that the ballots were cast by election day, just like any voter who went to the polls.

UW Law: Why are these laws that allow states to count ballots after Election Day important?

LS: These laws are incredibly, incredibly important for enfranchising, our members of the military. They're incredibly important for enfranchising voters who happen to be out of state at the time they cast their ballot — college students often fall into this category. They're incredibly important for disabled voters, who often can't vote unless they're voting by mail ballot.

UW Law: How do the Election Day statutes factor into Bost v. Illinois State Board of Elections?

LS: The argument that Congressman Bost and the other plaintiffs in this case have made is what we call extended receipt deadlines like these are preempted by federal law. Specifically, two federal laws that we call the Federal Election Day statutes. And what those statutes do — the only thing they do on their face — is set a national election day for congressional and presidential elections for the Tuesday after the first Monday in November.

UW Law: What brought about Bost v. Illinois State Board of Elections?

LS: It began when a Republican member of Congress named Mike Bost from Illinois, a state Republican Party official and a Republican Illinois voter who had previously served as a presidential elector, sued in federal court in Illinois. And they sued on this theory that I mentioned that the Federal Election Day statutes made it unlawful for Illinois to accept any ballot submitted by mail if they were received after election day, even if they were postmarked by election day. So, even if it was clear that the voter had voted the ballot by election day,

UW Law: What was specifically at issue when the case made its way to the Supreme Court?

LS: The question that was presented to the U.S. Supreme Court in that case was specifically whether Congressman Bost, the Republican who challenged Illinois's mail voting law, had standing to bring the case to begin with. And standing is a constitutional requirement. If you're going to file a lawsuit in federal court, you have to show that you've been injured in some way by the law that you're challenging, and if you can't show that to the satisfaction of the court or in meeting the standing test that courts apply, then you can't even get through the courthouse doors. The court won't even answer, look at the merits of your question. So, the the question that got to the U.S. Supreme Court was merely on this issue of standing because that's what the lower courts ultimately dismissed the case on.

UW Law: What was the Supreme Court's decision?

LS: What the U.S. Supreme Court decided is effectively that candidates can challenge election laws that govern the rules of the road in elections that they are running in. This was, I think, a significant difference from standing decisions in the past, that it — at least when they'd related to candidate standing — at least insinuated that the injury really belonged to the voters who were going to vote for the candidate or would have voted for the candidate and not to the candidate themselves.

UW Law: How will this case affect candidates?

LS: So, hands down, the biggest impact that this case will have is it will make it much, much easier for candidates to bring suit to challenge election laws in elections that they're running, and that means it'll make it much, much easier for candidates to get over this initial threshold of standing to say can you even be in this court making these arguments?

UW Law: How will it affect voters?

LS: So, the decision on its own is unlikely to have a direct impact, but as I mentioned, it will make, I think, election litigation much easier to bring. And that, of course, could, down the line, impact voters, depending on how courts decide those pieces of litigation. I think one thing that's really important for voters to be aware of is just because a candidate sues over an election law, that doesn't make the law illegitimate. We are seeing a proliferation of litigation over the past five years where candidates or political parties or political groups are trying to use the judiciary to make it harder for Americans to vote in their elections. And I have to say, this is a new thing.

UW Law: What's the overall impact you see that this case will have on elections?

LS: I think we've entered an era where you're just going to see, as a matter of course, an overwhelming amount of litigation surrounding elections. Like I mentioned, this is not how it always was, but with this decision, the court has effectively blessed that type of litigation, and we should expect to see more of it.