COLUMBUS, Ohio – When two of his Republican rivals for an Ohio Senate seat nearly came to blows on live statewide television two years ago, JD Vance appeared unimpressed.

“Sit down. Come on,” said Vance, the youngest and least politically experienced of the remaining candidates sitting in a row on stage. “This is ridiculous.”

To many observers, his calm, self-possessed reaction gave Vance an adult-in-the-room authority over his opponents. When Ohio Right to Life endorsed him a couple of weeks later, the group cited his “statesmanship” among the reasons.

Vance’s debating skills also caught the eye of Donald Trump, who endorsed him in that winning 2022 Senate bid and chose him to be his running mate in this year’s presidential election. His early encounters offer a sense of how the Yale-educated senator could approach Tuesday night’s vice-presidential debate, when he meets Kamala Harris’ running mate, Minnesota Gov. Tim Walz. It is the only time the two are expected to meet during the campaign.