Jeb Bush formally ended his campaign for president Saturday night after a dismal showing in South Carolina's primary. But it had been clear for months that the former Florida governor's chances of being the Republican presidential nominee were close to zero.

How did the man who entered the race in the summer of last year as the clear favorite -- with the famous last name, money at the ready and a résumé of policy innovations and successes -- wind up as an afterthought in the race long before voters actually started voting?

The reasons are many and complex, but, at root, they all come back to this basic fact: Jeb Bush is a fundamentally decent man who was badly miscast in the 2016 presidential race.

Bush was, and is, a soft-spoken policy wonk raised in a family that produced not one but two presidents. He is polite. You might even describe him as genteel. He is a rule-follower. And he is simply not all that into the campaigning end of politics.

Bush's long-held and well-known disdain for the nitty-gritty of modern campaigns was why I was stunned when it became clear in early 2015 that he was going to run for the Republican nomination. But even then, there were signs that Bush might not fully grasp the realities of the process.

Candidates who have dropped out of the 2016 race so far, and why

Republican presidential candidate John Kasich reacts while announcing he will end his campaign Wednesday, May 4, 2016 at The Franklin Park Conservatory and Botanical Gardens in Columbus, Ohio. (Kyle Grillot)

"The decision will be based on 'can I do it joyfully?' because I think we need to have candidates lift our spirits," Bush told CNN way back in January 2014 when talking about whether he would run for president. By December of that year, when it was clear Bush was all but in, he told a group of CEOs: "I kinda know how a Republican can win, whether it's me or somebody else -- and it has to be much more uplifting, much more positive, much more willing to be, 'lose the primary to win the general' without violating your principles."

Bush's first forays as an actual candidate -- he didn't announce formally until June 15 but was running hard long before that -- affirmed the sense that he just might be out of his depth in the race. He was halting and awkward -- at times seemingly baffled by the angry, in-your-face conservatism that confronted him on the campaign trail. His allies insisted this was all the result of a bit of rust; after all, Bush hadn't run for any office since 2002. He would get better, they insisted. Plus, his Right to Rise super PAC was on its way to raising $100 million in the first six months of 2015 -- an insurance policy against any problems Jeb might have as a candidate.

What no one in Bush world, especially Bush himself, seemed to grasp was how much the Republican Party had changed in the decade since he'd left the Florida governor's office. The presidency of Barack Obama had radicalized the GOP, making its base not only more conservative but more prone to embrace extreme rhetoric to counter the frustration and fury that Obama and his policies had generated in them. The Republican base no longer wanted politicians who could offer up alternative policy solutions to undo what Obama had done. They wanted someone who would blow everything up. Everything.

Enter Donald Trump. Trump got into the race on June 16, one day after Bush -- a remarkable symmetry given how big a role Trump would play in Bush's demise.

At the start, Bush, like virtually everyone else in Republican politics, regarded Trump as a sideshow, an entertainer whose bombastic rhetoric would go nowhere. Bush ignored him.

But Trump, from the start, was focused on Bush, whom he dismissed as a "low energy" candidate relying entirely on his family connections. In many ways, Trump defined his candidacy as the antidote to Bush-ism, painting himself as an anti-establishment truth teller with deep pockets who was dependent on no one.  Trump's attacks on Bush's family -- most notably his insistence that the Sept. 11, 2001, terrorist attacks proved George W. Bush had not kept the country safe as president -- signaled just how deep his animosity toward the Bushes went.

It worked. And kept working. By the time Bush and his team finally realized that Trump wasn't going away and that the former Florida governor needed to take him on rather than ignore him, it was already too late. Trump had effectively cast Bush as the sort of wishy-washy, boring and cautious politician that Republicans had been shoving down the throat of its base for years.

Bush tried to shake the patrician label, but he was visibly uncomfortable as an attack dog. "Donald Trump is a jerk," became a favorite Bush line on the stump, an "attack" that only seemed to reinforce the idea of Jeb as too kind for the race he was running in. (If "jerk" is the worst thing you can say about someone, then you really aren't saying much bad at all.)

For the past six months, at least, it was clear that Bush was effectively an afterthought in the race -- passed not only by Trump and conservative favorite Sen. Ted Cruz (R-Tex.) but also, most gallingly for Bush, by his onetime Florida mentee, Sen. Marco Rubio. (Rubio's smackdown of Bush in a late October debate -- "The only reason you're [attacking me] now is because we're running for the same position. Someone convinced you attacking me is going to help you." -- served as a dramatic the-student-has-now-become-the-master moment.)

While Bush, smartly, turned all of his rhetorical fire on Trump over the final two (or so) months of his campaign, his super PAC bafflingly continued on a deeply misguided strategy of bashing Rubio, Cruz and even Ohio Gov. John Kasich. Trump was largely ignored by Right to Rise's tens of millions of dollars in attack ads, a giant mistake given that the only possible path to a Bush comeback was to destabilize the race by dethroning Trump.

Bush's sixth-place finish in Iowa surprised no one. His fourth-place finish -- edging out a stumbling Rubio -- in New Hampshire only prolonged the misery.  As soon as polls closed at 7 p.m. Eastern in South Carolina on Saturday, it was clear that the surprise Bush was hoping for wasn't coming.

His speech suspending his campaign was moving and heartfelt -- a man with a genuine commitment to public service and to the conservative cause faced with the blunt reality that now was simply not his time.

Former Florida governor Jeb Bush announced to supporters in South Carolina that he was suspending his presidential campaign after a disappointing performance in the state's GOP primary. (AP)

"I have had a front-row seat to this office for much of my adult life," Bush said. "I have seen fallible men rise up to the challenges of our time, with humility, and clarity of purpose … to make our nation safer, stronger, and freer."

And he clearly had Trump on his mind even in his last moments as a candidate. "I firmly believe the American people must entrust this office to someone who understands that whoever holds it is the servant, not the master," Bush said.

Jeb Bush leaves the presidential race badly bruised by a Republican electorate that seems to want a bar-room brawler, not the captain of the fencing team, as its nominee. His campaign deserves blame for not realizing that Trump was serious from the get-go and not adjusting Jeb's gentlemanly pitch to better fit the electorate. But, at the most fundamental level, who Jeb Bush has been for the entirety of his 63 years on earth was fundamentally at odds with what Republican voters wanted in this election.

This was a wrong-place, wrong-time race for Jeb. He was never, ever going to win in a year like this one. Unfortunately, he realized that fact after suffering through a series of humiliations that made up his campaign for president.