Wheaton College students who plan to vote by mail in the Tuesday, Nov. 3 midterm election cannot use the campus post office to send their ballots.

The Wheaton College Post Office, known as the CPO, lacks the official government postmarks that election authorities may need to confirm a ballot was mailed on time, according to a report first published by The Wheaton Record. Students must instead take their ballots to the downtown Wheaton U.S. Postal Service branch, where a clerk can stamp them with an official postmark.

"It's very important that they go to a downtown Wheaton post office and hand it to a clerk who will then stamp it officially," Janice Diaz, Wheaton College's postmaster for 26 years, told The Wheaton Record.

The CPO is not a government post office. It does not carry official seals or stamps, Diaz said. Without those markings, election commissions may not be able to verify that a ballot was mailed within the required window. Diaz added that the CPO returns sensitive mail that lacks a CPO box number to the sender rather than forwarding it.

The downtown Wheaton USPS branch is open Monday through Friday from 9 a.m. to 4 p.m. and Saturday from 9 a.m. to noon. It is closed Sundays.

Last mail collection runs until 5 p.m. on weekdays and noon on Saturdays.

Illinois voters must apply for a mail-in ballot by 5 p.m. Oct. 29, and the ballot must be postmarked by Election Day, Tuesday, Nov. 3, according to the Chicago Sun-Times' Illinois voter guide. County clerks recommend mailing ballots at least a week before the election because of potential USPS delays. That puts the practical mailing deadline around Oct. 27.

The warning is a longstanding issue tied to the CPO's status as a private campus mail facility, not a result of new federal rules. President Donald Trump signed Executive Order 14399 on March 31, directing the Postal Service to develop new requirements for ballot mail, including specific envelope markings and barcodes. But the U.S. Supreme Court voted 7-2 on Sept. 14 to uphold a preliminary injunction blocking those rules through the November election, as The Conversation reported. Justices Clarence Thomas and Samuel Alito dissented.

Abby Simmons, a Wheaton College junior from Arizona, told The Wheaton Record she plans to vote by mail in Maricopa County. She said she stays registered there because she knows the local issues better.

DuPage County early voting began Sept. 24 at five locations, with two dozen more sites opening Oct. 19. On Election Day, Tuesday, Nov. 3, polls are open from 6 a.m. to 7 p.m.