Sen. J.D. Vance, R-Ohio, attends a campaign rally, March 16, 2024, in Vandalia, Ohio. (AP Photo/Jeff Dean, File)

As the Republican National Convention kicked off in Milwaukee Monday, former President Donald Trump announced that his running mate for the 2024 presidential election will be Ohio Sen. JD Vance, a former vocal critic of Trump.

Trump made the announcement via Truth Social on Monday afternoon, less than two days after surviving an assassination attempt during a rally in Pennsylvania. He posted the announcement as delegates were formally nominating him for the Republican nomination.

Vance’s national political career officially began less than two years ago, when he was sworn in as Ohio’s junior U.S. senator on Jan. 3, 2023. Vance defeated former U.S. Rep. Tim Ryan (D) in the 2022 midterm elections by 252,625 votes (53%-47%). Prior to his election, Vance served in the Marine Corps as a military journalist in the Iraq War before graduating from Ohio State University and later Yale Law School.

Vance gained national fame in 2016 when he released a memoir titled “Hillbilly Elegy,” which was later adapted into a 2020 Netflix film. While promoting the book, Vance claimed that he was a “never Trump guy” during an October 2016 interview with Charlie Rose.

“I’m a ‘Never Trump’ guy. I never liked him,” Vance said. “And I — but I noticed this willingness from people who think a lot like I do that, look, we told you so. To all these white working-class voters, we told you so. We told you that Trump was going to be a terrible candidate. We told you that you were an idiot if you voted for him.”

Vance later worked as a contributor for CNN before he co-founded a Cincinnati-based venture capital firm called Narya. During his millionaire-backed Senate run in 2022, where Vance positioned his policy ideas ever closer to Trump, text messages sent by Vance in 2016 surfaced and revealed how much he despised the then presidential candidate.

“I go back and forth between thinking Trump is a cynical asshole like Nixon who wouldn’t be that bad (and might even prove useful) or that he’s America’s Hitler,” Vance wrote. “How’s that for discouraging?”

Since becoming a senator, Vance has take far-right positions on issues like no-fault divorce, contraception access and climate change.

Despite his record of harsh statements on Trump, Vance flipped his position entirely and been an adamant champion of the former president. Should Trump win reelection in November, Vance will be the second in line for the presidency and possibly a Republican candidate for president in future elections.