When he re-emerged, a chastened, rawly emotional Mr. Sanford made an extraordinary public appearance that was part confessional and part personal therapy session. He explained, rambled, apologized, rambled some more, teared up, and announced that “I have spent the last five days crying in Argentina.” Whether the “Evita” allusion was deliberate or not has always been a mystery.

Mr. Sanford’s marriage fell apart; he is no longer engaged to his Argentine girlfriend, having announced the demise of their relationship via a 2,346-word Facebook post several years ago. It has been a hard experience to live down. “There was public shame,” said Mr. Sanford, who has a habit of talking about himself in the second person, and who still takes the More is More approach to discussions of his private life. “There was public failure. You wish you could redo a lot of the things you did.”

After the football game, he was being driven back to Charleston, where he has a house (he also has a farm an hour away). The driver was John McKinney, a 23-year-old graduate of Eastern Kentucky University who, at least at that moment, constituted a full 50 percent of Mr. Sanford’s campaign staff. After reading on Twitter that Mr. Sanford wanted to run, he said, he had felt energized by the candidate’s desire to bring the Republican Party back to its core values. He called the next day to sign up.

It was unclear how much money Mr. McKinney could hope to earn from working for Mr. Sanford, who is facing some fund-raising challenges.

“You’ve got to recognize in this endeavor — from a capital standpoint, you’re going to be deprived of the big spenders, because no one’s going to risk going against Donald Trump,” Mr. Sanford said. “The A Team is not going to work for you, and even the B Team isn’t going to do something that might end in a few months.”

“I don’t mean you’re on the C Team,” he said to Mr. McKinney, who was trying to negotiate the chaotic drive away from the football stadium. “You want to get in the left lane now, so we can turn.”