With the first contest of the presidential campaign over and the second one coming in a few days, the enormous Republican field is winnowing fast. So what can we learn from each of the candidates who have left, or who will probably soon leave? Each in their own way, they show us something about the state of today's Republican Party and the realities of presidential politics. Let's look at them one at a time, starting with the one who most recently packed his bags:

1. Rand Paul. Paul was, as everyone said for so long, the most "interesting" political figure in Washington, a Republican with libertarian leanings who seemed unafraid to challenge his party on certain issues, and proved adept at garnering positive media coverage. But on Wednesday he pulled out of the presidential race, which showed that the "libertarian moment" of which Paul's candidacy was supposed to be a part didn't actually last more than a moment. It turned out that in the context of a presidential primary, the occasional heterodox opinion doesn't make you "interesting," it makes you unpalatable. Paul could make a strong case for prison reform or a less interventionist foreign policy, but the operative question in today's GOP isn't whether you have a strong case to make, but whether you're a pure and trustworthy conservative.

2. Mike Huckabee. Huckabee pulled out of the race on the night of the Iowa caucuses, after airing an almost surreal ad whose message seemed to be that Iowa is a soul-sucking tundra of misery, and Mike Huckabee couldn't wait to end his desultory journey through its 99 counties of despair — all to the tune of Adele's "Hello." (Sadly, the video has been removed from YouTube). The 2016 version of Huckabee was no different from the man who ran eight years ago: the same friendly manner, the same fervent faith, the same extemporaneous eloquence born of years in the pulpit and behind a microphone. But he failed because political lightning — in the form of an Iowa victory granted to the favorite of evangelical voters — only strikes once. Go back to those voters later, and you'll learn they've found a new shiny object. Without the tools of money and organization, he couldn't repeat his success.

3. Rick Santorum. Santorum was the surprise winner of Iowa four years after Huckabee and did even worse this time around. That's because of the same reasons Huckabee couldn't succeed, but also because he's Rick Santorum, someone so unpleasant that he makes you think, "You know, I'd like to spend some time hanging out with Ted Cruz."

4. Rick Perry. Before the race began, Perry looked incredibly strong. At the end of his tenure as the nation's longest-serving governor in the nation's biggest conservative state, he had fundraising ability, a record to point to, and impeccable anti-Obama credentials. How many candidates could say they kept one million of their own poor citizens uninsured just to give Barack Obama the finger? That's commitment. Perry even had stylish new glasses. Time magazine published an article in July 2013 titled, "Can Anyone Stop Rick Perry In 2016?"

So why did Perry's bid go nowhere? It turns out that you can have a second chance in Republican presidential politics — with the exception of George W. Bush and Gerald Ford, every GOP nominee since Barry Goldwater got the party's nod only on their second try — but only if in your first try you did quite well, coming in second place and leaving lots of admirers behind. The trouble for Perry is that everyone's memory of his 2012 candidacy was that awful "Oops" moment (which may have been brought on by painkillers). In other words, he had the mark of a loser, not of someone who almost won.

5. Scott Walker. Walker was supposed to be the guy who could unite all the GOP factions: beloved by the economic conservatives for his zeal for crushing unions, not a Washington insider so the tea party would like him, able to the talk to the evangelicals (an evangelical himself, Walker is the son of a Baptist minister). What wasn't to like? But Walker's demise demonstrated that it isn't enough to look great on paper. There's a quality that great politicians have, like great movie stars: a charisma that draws people to you and makes them want to be persuaded by you. However you might define it, Walker didn't have it. He left voters thoroughly underwhelmed, and the longer he stayed in, the more obvious it became.

6. Bobby Jindal. Jindal was once a conservative wunderkind, a young man everyone thought was going places. But once he got there, he didn't do so great; his tenure as Louisiana governor was miserable, and all that was left of that young man in a hurry was an adult who still looked 17 years old.

7. Lindsey Graham. Despite his focus on national security — which essentially consisted of saying, "We're all gonna die!" whenever any such topic was brought up — Graham was a little too friendly for this year's Republican electorate. He couldn't muster the bitter hatred that animates someone like Ted Cruz, and for which voters seem to be yearning. But if he's lucky, his campaign could get him the secretary of defense job one day, which you sense is what he really wants.

8. George Pataki. Pataki ran on the theory that what Republicans wanted was a pro-choice former governor who left his last office nearly a decade ago, and who's so bland his own dog probably doesn't recognize him. That turned out not to be the case.

9. Carly Fiorina. Fiorina's path to the White House, which involved getting fired from a CEO job, then losing a bid for Senate, then deciding she'd like to be president, was just a bit too...let's say unconventional. She'll be gone soon.

10. John Kasich. Kasich has been doing pretty well in New Hampshire, but he freely admits that he'll have to do very well there in order to stay in the race: "If we get smoked here, I'm going home," he says. But Kasich never had a chance. A guy who talks proudly of his time as chairman of the Budget Committee in Congress, who's extremely conservative but doesn't seem angry about it, who accepted the expansion of Medicaid, who seems comfortable with the fact that complex policy questions sometimes require complex answers, whose deep religious faith pushes him more in the direction of caring and less in the direction of smiting? That's not what today's Republicans want.

11. Jim Gilmore. Fun trivia fact: Jim Gilmore is also a candidate for president in 2016.

And that brings us at long last to…

12. Jeb Bush. Bush offers perhaps more lessons than anyone else. Yes, his support of Common Core and his penchant for talking about undocumented immigrants as though they're human beings did him no favors. But a different candidate might have overcome that. The ineffectiveness of all the money spent by Bush's super PAC reminded us that money is a necessary but not sufficient condition for success, even in nine-figure quantities, and that while every Republican candidate needs at least one or two billionaires in his corner, they can't actually buy the election for their favored candidate. He showed that "the establishment" is most likely to support candidates it's comfortable with, not the best candidates. He showed that escaping the legacy of George W. Bush's presidency is difficult for any Republican, but infinitely more so if you're his brother. He showed that Republicans wanted something new and different. But most of all, Bush was just extraordinarily ill-suited to run for president, particularly in the current moment. After watching him for a year, one might conclude that he'd make a perfectly passable junior vice-president of some large corporation that sells insurance or paper clips. But the leader of the free world? No.

But for all his advantages in politics and in life, it's hard not to feel sorry for Bush. As The New York Times reported Wednesday, he delivered a "fiery riff" to a New Hampshire audience about what kind of commander in chief he'd be, which closed this way: "'I won't be out here blowharding, talking a big game without backing it up,' he said — and was met with total silence. 'Please clap,' he said, sounding defeated."

It would be hard to come up with an image that more perfectly synopsized Bush's campaign. There he stands, his discomfort on display, trying against his own nature to sound tough, offering a weak criticism of candidates who have passed him by, and finally imploring his audience to render at least a momentary positive reinforcement before they turn away from him forever. Please, he says, validate this strange and miserable journey I've undertaken. If nothing else, show me just a bit of merciful kindness as my final defeat approaches. Please, I beg of you. Please clap.