J.D. Vance called Trump 'America's Hitler,' was pro-trans surgery and his wife 'hates' politics. So why DID Donald pick him as his Vice President? Insiders reveal the REAL reason...

'Unfit for our nation's highest office', 'America's Hitler' and 'reprehensible' aren't traditional labels for an aspiring running mate to attach to his party's standard bearer.

But it's worked for Senator J.D. Vance.

On Wednesday evening, the Ohio native will address the Republican National Convention in Milwaukee as the GOP's presumptive vice presidential candidate completing his transformation from self-declared 'Never Trumper' to MAGA diehard.

And political insiders say it is because of his once savage criticism of Trump that he has emerged as one of the party's most effective advocates.

'I go back and forth between thinking Trump is a cynical a**hole like Nixon who wouldn't be that bad (and might even prove useful) or that he's America's Hitler,' Vance privately wrote to a friend on Facebook in 2016.

After Trump defeated Hillary Clinton to become president, the Marine veteran, Yale law school grad, best-selling author and Silicon Valley venture capitalist doubled down, writing in a since-deleted tweet: 'In four years, I hope people remember that it was those of us who empathized with Trump's voters who fought him the most aggressively.'

But skip forward four years and it was Trump batting away Vance's advances and openly mocking him at a rally to support the then-candidate's Ohio senatorial campaign.

'J.D. is kissing my a**. He wants my support so bad,' Trump told the pro-Vance crowd. 'Yeah, he said some bad things about me, but that was before he knew me and then he fell in love.'

Trump's remarks drew a collective wince, as Republican Rep. Barbara Comstock told CNN: 'He made J.D. Vance look like a mouse, not a man. It was humiliating.'

However, Republican commentator and consultant Scott Jennings, who has worked alongside Vance as a political pundit, told DailyMail.com there's much more to this story.

'He provides the best defense and intellectual argument for Trumpism and MAGA,' said Jennings. 'He's really good on television and he's really good at being a surrogate.'

Over the past several years, Vance has shown he's more than willing to spar with Trump's detractors, even on the most controversial topics.

As recently as February, Vance jousted with ABC News anchor George Stephanopoulos, who pressed him over whether he would have certified the results of the 2020 election as Vice President Mike Pence did.

'I know you guys are obsessed with talking about this,' he fired back, before launching into a laundry list of perceived problems with the 2020 election, including mainstream media and social media censorship of criticism of Biden.

Vance also did not shy away when he was asked in May about a New York civil court jury determining that Trump sexually abused journalist E Jean Carroll nearly three decades ago.

'I think fundamentally the lawsuit is about something that happened 25 years ago,' Vance told CNN host Wolf Blitzer. 'It's a "he said, she said" situation, and I trust my friend and the guy that I've known and gotten to know.'

Then on Saturday, almost immediately after Trump narrowly survived a failed assassination attempt at a Pennsylvania political rally, Vance pointed the finger squarely at Biden.

'Today is not just some isolated incident,' he tweeted. 'The central premise of the Biden campaign is that President Donald Trump is an authoritarian fascist who must be stopped at all costs. That rhetoric led directly to President Trump's attempted assassination.'

His comment provoked intense backlash with former Republican Congressman and fierce Trump critic Adam Kinzinger saying the remarks should 'disqualify him' from becoming Vice President. Though, it may have been exactly what the Trump team wanted on the airwaves.

'What a campaign has to do every day is communicate, every day they have to create content,' Jennings told the Mail. 'Vance's communication skills are going to be invaluable. He is going to be the chief surrogate for the ticket.'

So who is J.D. Vance - a skilled newcomer and potential heir to the MAGA movement or a craven political chameleon?

Vance grew up in some of America's most poverty-stricken places – ping-ponging between the hollers of Appalachia in Jackson, Kentucky and the declining towns of the Rust Belt in Middletown, Ohio.

His parents divorced when he was 6 years old – when his mother told him that he'd never see his dad again. 'It was the saddest I had ever felt,' he wrote in his best-selling, award-winning memoir Hillbilly Elegy. 'Of all the things I hated about my childhood, nothing compared to the revolving door of father figures.'

For the rest of his young life, Vance lived primarily with his grandmother 'Mamaw' in Middletown while his mother battled opioid addiction.

After graduating from Middletown High School, he enlisted in the US Marine Corps and was deployed to Iraq for six months in late 2005 as a combat correspondent in the Public Affairs divisions.

He wrote about the experience, describing it as the most defining period in his life – and recalled a life-changing encounter with a shy Iraqi schoolboy during a community outreach mission amid the Iraq War.

'I gave him a small eraser, his face briefly lit up with joy before he ran away to his family, holding his two-cent prize aloft in triumph. I have never seen such excitement on a child's face,' Vance wrote.

That moment, Vance recalled, pushed him to come to grips with the resentment he carried from his difficult upbringing.

'I began to appreciate how lucky I was: born in the greatest country on earth, every modern convenience at my fingertips, supported by two loving hillbillies, and part of a family that, for all its quirks, loved me unconditionally.

'I resolved to be the type of man who would smile when someone gave him an eraser. I haven't quite made it there, but without that day in Iraq, I wouldn't be trying.'

When Vance returned home from his deployment, he attended the Ohio State University, graduating with a degree in political science and philosophy. He then went on to study at Yale Law School, where he met his wife, Usha Vance.

'She seemed some sort of genetic anomaly, a combination of every positive quality a human being should have: bright, hardworking, tall, and beautiful,' he wrote.

They married in Kentucky in 2014 and went on to have three children, Ewan, Vivek and Mirabel, moving to San Francisco in 2015 where Vance went to work for billionaire Peter Thiel's investment firm, Mithril.

In 2016, he published 'Hillbilly Elegy' and began to build his public profile – appearing on television as a de facto expert on America's struggling white working-class.

Vance moved back to Ohio and co-founded a Cincinnati-based venture capital firm Narya, which focused on promoting technology start-ups in America's heartland.

The couple bought a 5,000-square-foot Victorian Gothic house on the east side of Cincinnati for $1.4 million, before reportedly adding a second $1.5 million home in Alexandria, Virginia, to their portfolio in 2023.

Usha Vance's political leanings are unclear, but she was reportedly a registered Democrat until at least 2014 and has been described by colleagues as a liberal or moderate.

Regardless, Trump has reportedly taken a shine to her.

Last month, Trump asked Usha how she liked political life. When she gave a noncommittal answer, Trump quipped that his wife Melania hated it too, making Usha laugh, according to The New York Times.

In February 2021, Silicon Valley heavyweight Peter Thiel brokered a meeting between Trump and Vance at Mar-A-Lago, as the political novice ramped up his Senate run. The get-together appeared to start poorly as Trump sat behind his desk with a pile of research that documented all of Vance's past criticisms of the former president.

Vance reportedly apologized and then surprised Trump by not asking for his endorsement. Trump was reportedly drawn in by Vance's physical appearance, repeatedly commenting on his 'beautiful blue eyes', trim physique and fitted suits.

Since that meeting Vance has become an outspoken Trump advocate and defender, winning the former president's endorsement and powerful allies in the Trump family.

'J.D. is a great and loyal guy who has become a genuine friend,' Don Trump Jr. told DailyMail.com recently. 'His entire life story is the embodiment of the American dream, but he never forgets where he came from.'

Vance's political and social stances have also shifted with time.

He referred to abortion as murder last year and ran on a 15-week abortion limit platform in 2022 but has since softened his stance to more closely resemble Trump's position that states should determine abortion limits and make reasonable expectations for rape, incest and the life of the mother.

One of his former close friends from Yale, Sofia Nelson, who is transgender, told The New York Times that Vance had brought home-baked treats round after they underwent top surgery.

But then Nelson said their friendship broke down after he supported an Arkansas bill opposing transgender care for minors, and now they no longer speak.

Vance has also criticized America's support of Ukraine in their war against Russia and has called for continued backing of Israel.

Jennings conceded that some of Vance's views – particularly his isolationist bent – will rub some in the party the wrong way: 'He's not a traditional conservative. He's got interesting politics that are not orthodox Republican views.' Though, Jennings said, 'Vance arrives at his positions in a thoughtful way - he arrives at them honestly.'

Whatever beliefs Vance now holds – either about Trump or the critical issues facing America - he has certainly been welcomed back into the MAGA fold.

Perhaps, like that shy boy he encountered as a Marine in Iraq, J.D. Vance is showing Donald Trump how truly grateful he can be.