Pope Leo XIV has submitted a mail-in ballot in Illinois for the upcoming US midterm elections, becoming the first pope in history to vote in an American election.

"Pope Leo XIV has exercised his right to vote as a United States citizen, whenever he was eligible to do so," the Holy See Press Office said, noting that this included his years in Peru.

The Chicago-born pontiff is the first US citizen to hold the Vatican's highest office, following his election in May 2025.

"The Holy Father expresses his belief in the right and the duty of citizens to participate in democratic processes," the press office said in a statement.

According to reports, the Pope requested his mail-in ballot from the Will County Clerk's Office on 3 October.

Less than two weeks later, the Vatican announced he had undergone surgery to remove the lower lobe of his right lung after being diagnosed with lung cancer.

The Vatican confirmed last week that the 71-year-old pontiff will travel as planned to Uruguay, Argentina, and Peru in early November.

The US midterm elections will determine which political party controls Congress and are expected to have a significant impact on the final years of Donald Trump's presidency. Elections will be held nationwide on 3 November, though early voting has already begun in most states.

Relations between Pope Leo and the Trump administration have been strained since April, when the Pope called for peace following US-Israeli strikes on Iran. The two have also clashed over immigration enforcement.

"I don't think he's doing a very good job," Trump said of the Pope. "We don't like a Pope that's going to say that it's OK to have a nuclear weapon. I'm not a big fan of Pope Leo."

Pope Leo responded with his own remarks, saying: "The mission of the Church is to preach the Gospel, to preach peace."

"If someone wants to criticise me for preaching the Gospel... I hope simply to be listened to because of the value of God's words."