In picking Sen. JD Vance (R-Ohio) as his vice-presidential running mate, former President Donald Trump has tapped someone who just years ago was one of his most prominent conservative detractors and is now one of his most dogged defenders on Capitol Hill and in the press.

The selection of Vance over his rivals Sen. Marco Rubio (R-Fla.), whose involvement in a compromise immigration reform bill in 2013 has always made him suspect in the MAGA world, and North Dakota Gov. Doug Burgum, a wealthy tech entrepreneur favored by some Republican business elites is sure to rev up Trumps populist base. And Trump, who prizes fealty above all, has chosen someone he believes he can count on.

This I know: He will faithfully stand by Donald Trumps side as they win this election and change the course of our nation, Ohio Lt. Gov. Jon Husted said at the Republican National Convention on Monday as he formally nominated Vance for vice president.

Vance became a household name in 2016 when he released the bestselling memoir, Hillbilly Elegy, which recounted his mothers struggles with drug addiction and his path from an impoverished childhood into the U.S. Marine Corps and to Yale Law School.

The book was a hit among educated liberals following Trumps election, both because he offered insight into the experience of low-income white voters that make up a key part of Trumps base and because he was an impassioned critic of Trump.

He characterized Trump as cultural heroin for Americans in distressed communities looking for easy solutions to their problems.

He never offers details for how these plans will work, because he cant, Vance wrote in The Atlantic in 2016. Trumps promises are the needle in Americas collective vein.

But when Vance ran for Senate in the 2022 election cycle, he expressed regret for his past criticism, claiming he now approved of Trumps performance as president. Vance nurtured a relationship with Trumps eldest son, Don Jr. , which helped him lock up Trumps endorsement in the Buckeye States competitive primary.

Whether moved by the zeal of the convert or something more cynical, by 2021, Vance had become a leading purveyor of red meat for the MAGA movement and staunch ally to Trump.

In a July 2021 interview with then-Fox News host Tucker Carlson , Vance said the country was being run by childless cat ladies. He delivered a speech in Nov. 2021, titled, Universities are the Enemy.

In addition, Vance affirmed this past February he would not have voted to certify the 2020 presidential election and would have advocated for the inclusion of alternate slates of electors. He has also called for Trump to fire every civil servant in the administrative state, and said Trump can defy Supreme Court orders if the high court issues an illegitimate ruling.

Regardless, Democrats are already using old Vance quotes against him.

JD has a body of anti-Trump statements that can be exploited, David Axelrod, who advised former President Barack Obama , told the New York Times in a Friday article.

Here are 3 more takeaways:

Trump Has Picked A Major Critic Of U.S. Support For Ukraine

In keeping with Vances status as a more fleshed out avatar for America First ideology than anyone but Trump himself, Vance is among the Senates biggest critics of U.S. aid to Ukraine.

Vance, who voted against the latest military and economic aid package to Ukraine, argued in a New York Times op-ed in April that the United States lacks a plan to overcome Russias manpower advantage over Ukraine. He instead called for recognizing that Ukraine would need to make territorial concessions to achieve peace.

The Biden administration has no viable plan for the Ukrainians to win this war, he wrote.

Vance is not a complete isolationist. He sees confronting China as a strategic priority for the United States and worries about depleting scarce U.S. military resources in Ukraine that could be used to shore up Taiwan.

But he has occasionally taken a flippant attitude toward the Ukrainian cause, such as when he refused to join a meeting with Ukrainian President Volodymyr Zelenskyy at the Munich security conference in February.

President Joe Biden s campaign can expect to get some mileage out of Vances heterodox foreign policy stances. Biden has touted the expansion of NATO under his watch as a major accomplishment and warned against the harm Trump, who is ambivalent about the groups role, might cause to the international military alliance.

Vances Message About The Attempt To Assassinate Trump Clashes With Trumps Pleas For Unity

Following Saturdays assassination attempt, in which a gunman shot Trump in the ear, the former president expressed gratitude to God and said he is rewriting his nomination acceptance speech to focus more on national unity.

Had this not happened, we had a speech that was pretty well set that was extremely tough, Trump told the Washington Examiner on Sunday. Now, we have a speech that is more unifying.

Vance had a very different reaction to the shooting, blaming Democrats for depicting Trump as a threat to the countrys democracy.

The central premise of the Biden campaign is that President Donald Trump is an authoritarian fascist who must be stopped at all costs, Vance wrote on X on Saturday night. That rhetoric led directly to President Trumps attempted assassination.

Theres no evidence yet to back up that charge. Biden said Sunday that federal authorities do not yet have any information about the motives of the deceased shooter, Thomas Matthew Crooks, a registered Republican who once gave a small sum to a liberal group.

Vance Could Help Trump In Key Swing States

Vance, who worked for conservative billionaire Peter Thiels venture capital firm in Silicon Valley, California, before entering politics, is not uncomfortable in elite settings.

Whats more, he does not automatically add a state to Trumps electoral map. Vances home state of Ohio is already reliably Republican.

But Vance, who was mostly raised by his Kentuckian mamaw and papaw, claims an authentic link to the working-class and low-income white communities that play a pivotal role in determining outcomes in the key swing states of Michigan, Wisconsin, and Pennsylvania.

Vance also combines support for immigration restrictions and other right-wing cultural causes with a populist stance on some economic issues that cuts across party lines. He has backed progressive Federal Trade Commissioner Lina Khans anti-monopoly agenda, collaborated with Sen. Sherrod Brown (D-Ohio) on a bill to tighten safety regulations for freight rail companies and teamed up with Sen. Elizabeth Warren (D-Mass.) on clawing back the compensation of the executives of big banks that fail.