In recent weeks, President Trump has continuously attacked the vote-by-mail system, falsely claiming it leads to widespread voter fraud. On September 2nd, the president suggested North Carolina voters should vote by mail, then in person, to test the system. “Let them send it in and let them go vote, and if their system’s as good as they say it is, then obviously they won’t be able to vote,” Trump said.

Voting twice is illegal, according to both state and federal law. 52 U.S. Code § 10307 states that someone who votes more than one time “shall be fined not more than $10,000 or imprisoned not more than five years, or both.”

Minnesota Secretary of State Steve Simon has warned against voting both by mail and in person. “It's like advising someone to try to rob a bank to see if the security is as good as the bank says it is. Knowingly voting twice is a felony. Period. Doing it creates a mess for the voter and the election administrators alike,” he said.

Experts say the president’s words are likely to increase uncertainty surrounding the upcoming election. Richard Pildes, a professor at the New York University School of Law, says President Trump’s comments “are only going to stir enormous confusion.”