The Jeb Bush campaign for president is over. After a disappointing finish in South Carolina on Saturday, he suspended his campaign shortly before 9 p.m., before it was even clear whether he would place fourth or fifth. The news of his exit didn’t come as a surprise given his poor showings in the first three contests this primary season, but if you had told most analysts a year ago how the Bush campaign would go, they would have been shocked. So just what the heck happened?

1. The party didn’t decide on Bush

The first indication that Bush was going to have some problems came almost a year ago, when prominent members of the Republican Party didn’t rally around his cause. My colleague Nate Silver and I first wrote about this in April 2015. Bush’s pace of endorsements was, at that point, far behind that of his brother George W. Bush in 2000, and behind that of other campaigns that romped to victory. Although he picked up a few more endorsements by the time he officially announced his bid in June 2015, it was clear Bush was facing a major problem.

Had the party leaders decided on Bush early, he may have been able to overcome some of his other weaknesses, such as relatively low poll numbers. Intra-party support may have forced other candidates from the field. Instead, the 2016 campaign saw a record number of candidates enter. Several of these candidates appealed to a similar set of voters as Bush (more on this in a moment) and gobbled up press attention. Even with millions of dollars raised by his campaign and super PAC, Bush was merely one of many.

2. Kasich did it better

For all of Bush’s early problems, primary campaigns are about winning and building momentum, and Bush had a chance to come in second in New Hampshire and potentially restart his campaign — even after finishing well behind in Iowa. Marco Rubio had an awful debate performance on the eve of the New Hampshire primary, and New Hampshire has historically been willing to give more moderate candidates a boost. Bush, though, could only manage fourth, and so didn’t get a bounce out of the Granite State.

Instead, it was John Kasich who won second place. Like Bush, Kasich held many events in New Hampshire. Like Bush, Kasich tried to run a policy-oriented campaign. Like Bush, Kasich pointed to his accomplishments as governor of a swing state. Unlike Bush, Kasich seemed content to allow the other candidates to quibble with each other on the debate stage, while he stayed positive. Thanks to his relatively strong performance in New Hampshire, Kasich now leads Bush nationally.

The upsetting thing for Bush is that Kasich entered the race very late and only after it became clear GOP elites weren’t coalescing behind Bush. A race with Donald Trump but without Kasich may have looked a lot different in New Hampshire. Indeed, if you add Bush and Kasich’s New Hampshire vote percentage to that of fellow New Hampshire-centric candidate Chris Christie, you get 34 percent, or just a little less than Trump’s 35 percent. That would have made for a very different storyline for Bush.

3. Voters wanted something fresh

We’ve known for a long time that this year’s Republican electorate is fed up with the way the country has been run. Many more Americans say the country is on the wrong track than heading in the right direction. And this year, voters are making their voices heard. You can even see that on the Democratic side, where Hillary Clinton, who started off in a much stronger position than Bush, has had her hands full with Bernie Sanders (who wasn’t even a Democrat until very recently).

On the Republican side, all of the leading candidates are fresh political faces. First-term Sen. Ted Cruz vanquished Mike Huckabee and Rick Santorum in Iowa. First-term Sen. Marco Rubio has had the most success within the endorsement primary and among mainstream conservatives, even as he fought against three politically savvy current and former governors. Oh, and there’s also that guy named Donald Trump, who has dominated the Republican landscape. Even political novice Ben Carson has been able to stick around.

The bottom line is that Bush, the son of one president and brother of another, and a veteran office-holder himself a decade ago, was the wrong fit for this political atmosphere.

4. Trump

Let’s be real: Trump upended the 2016 campaign, and Bush was his most prominent casualty. While Trump has attacked almost everybody, his biggest early target was Bush. As my colleague Allison McCann found in late August 2015, Bush was attacked more times on Twitter by Trump than all of the other candidates combined. Trump seemed to delight even in attacking Bush’s mother. And he had defied party orthodoxy by savaging George W. Bush for not preventing the Sept. 11 attacks, and for misleading the country into war with Iraq.

Whether or not Republicans love Trump (and many don’t, particularly the strongest economic and foreign policy conservatives), he garnered more media attention than anybody else. That meant the negative information flow directed against Bush was staggering. While candidates like Cruz, Kasich and Rubio stayed out of the firing line in the beginning, Bush was hit over and over. That pushed Bush’s poll numbers downward, and he never recovered. Bush’s support nationally was cut in half, from 12 percent on June 1 of last year to just 6 percent now, which is good enough for dead last. Bush is the only candidate left in the race who is polling more than a percentage point lower now than on June 1 of last year. Trump, meanwhile, is polling over 30 percentage points higher.

5. Voters just weren’t that into Bush

Whatever the reason that other candidates rose or faded, Bush had one big problem at the end of the day: Voters didn’t like him. You can see this in the chart below, which shows a three-poll rolling average of Bush’s net favorability rating among Republicans, according to YouGov, since Bush entered the campaign.

Bush’s net favorability in the latest three-polling average is just +5 percentage points, which is down 25 percentage points from when Bush announced his bid. It’s very difficult to win a party’s nomination when the number of party members who don’t like you is nearly equal to the number that do like you.