Mail-in ballots are back in the national spotlight as the U.S. Supreme Court prepares to hear a pivotal case from Illinois that could alter how millions of Americans cast their votes in future elections. The lawsuit, brought by Republican Congressman Mike Bost and two electors, challenges Illinois’ policy of counting mail-in ballots received up to 14 days after Election Day—as long as they’re postmarked by the deadline .
Table of Contents
- What the Case Is About
- Why Mail-In Ballots Matter
- Legal Arguments on Both Sides
- Broader Implications for U.S. Elections
- What Happens Next?
What the Case Is About
At the heart of the dispute is a narrow but critical question: Can a federal elected official sue to stop a state from counting mail-in ballots received after Election Day? Illinois law currently allows ballots postmarked by Election Day to be counted if they arrive within 14 days—a policy designed to ensure every vote counts, especially for overseas and rural voters.
Rep. Mike Bost, a six-term Republican from downstate Illinois, argues that this rule violates federal statutes that set Election Day as the uniform date for federal contests. His lawsuit, filed in May 2022, is one of several legal challenges backed by allies of former President Donald Trump, who has repeatedly—and falsely—claimed that mail-in voting leads to widespread fraud .
Why Mail-In Ballots Matter
Mail-in voting isn’t new—but its use surged during the pandemic, with over 46% of voters casting ballots by mail in 2020. States like Illinois, California, and Colorado have since expanded access, citing convenience, accessibility, and public health.
For many Americans—seniors, disabled voters, military personnel, and those in remote areas—mail-in ballots are not a convenience but a necessity. Eliminating grace periods for delivery could disenfranchise thousands whose ballots arrive late due to no fault of their own.
Legal Arguments on Both Sides
| Plaintiffs (Bost et al.) | Defendants (State of Illinois) |
|---|---|
| Argue federal law sets Election Day as the voting deadline. | Argue states have authority to administer elections, including ballot receipt windows. |
| Claim late-counted ballots dilute votes cast on time. | Point to safeguards like postmark verification and bipartisan oversight. |
| Say Congress—not states—controls federal election timing. | Cite precedent (e.g., Arizona v. Inter Tribal Council) affirming state election administration powers. |
Broader Implications for U.S. Elections
This case is just the first of several election-related disputes the Supreme Court will hear this term. Legal experts warn that a ruling against Illinois could trigger a domino effect, encouraging similar lawsuits in other states with extended mail-in ballot deadlines—including Pennsylvania, Nevada, and Michigan.
With the 2026 midterms—and the 2028 presidential race—on the horizon, the stakes couldn’t be higher. A decision restricting mail-in ballot counting could reshape voter turnout, particularly among Democratic-leaning demographics who use mail voting at higher rates.
What Happens Next?
Oral arguments are scheduled for Wednesday, October 8, 2025. A decision is expected by late spring or early summer 2026—well before the November midterms.
In the meantime, election officials in Illinois say they’re preparing for all scenarios, including potential changes to ballot processing protocols. Advocacy groups like the ACLU and Brennan Center for Justice are closely monitoring the case, calling it a “litmus test for voting rights in the post-2020 era.”
