It was just 43 days before the 2022 Republican primary in Ohio, and former President Donald J. Trump had yet to throw his weight behind a Senate candidate. J.D. Vance, a political novice competing in a packed field, had a huge problem.
He had publicly called Mr. Trump “loathsome” and an “idiot.” Once, he described him as “cultural heroin.”
Then came an unexpected lifeline. “Enough with the lies being told about this guy,” Donald Trump Jr., the former president’s son, wrote on Twitter, assuring his followers that Mr. Vance had become a fan of his father. A month later, encouraged by his son, the elder Mr. Trump endorsed Mr. Vance.
Today, Mr. Vance is one of the former president’s most reliable allies and a leader of a band of Republicans pushing Senate Republicans to the right. And his star has only continued to rise: Mr. Vance is on the list of Mr. Trump’s possible running mates, according to two people familiar with the discussions.
In no small part, Mr. Vance owes his quick ascent into the Trump orbit to his unlikely friendship and ideological kinship with the former president’s oldest son. They text or talk nearly daily and try to meet up if they are in the same city, according to people who know them both. They are a social-media tag team, often reposting each other’s messages.
Although he has stressed that the choice of a running mate is his father’s decision alone, Mr. Trump has said he would be happy with Mr. Vance on the G.O.P. ticket.
