And he appeared to be such a threat for so long...but turned out to be a Pawlenty repeat. Will Carson be this cycle's Cain? Fiorina the modern Bachman? Is Trump's ground-game real?

Suprised by Walker dropping out on one hand, but candidates like him need lots of money to keep going and once that dries up like it did with Perry, it's over for them. Fortunately for us, Huck is good at "living off the land" as the saying goes.

Hopefully we'll be the beneficiery of some of Walker's previous support.

Who gains the most from Walker’s exit?

It’s not who you think. The candidates who will benefit are the ones who have put themselves in position to capitalize on Walker’s exit. I look for the candidates who have shown commitment to Iowa by campaigning aggressively in Iowa to benefit the most. I think this helps a guy like Rick Santorum – first, because it helps him get on the main debate stage, and also because he also has a similar blue-collar message as Walker. It could also help Mike Huckabee, who, like Santorum, has a populist message and a campaign that is focused on rural support in Iowa.

Most people will expect that Walker’s exit should help candidates like Jeb Bush, Marco Rubio, and maybe a conservative like Ted Cruz. The problem is that those campaigns have yet to fully engage in Iowa. The reason you need to campaign aggressively in Iowa is because you never know when and where your opportunity will come.

Rubio has yet to even campaign in places like Dubuque or Waterloo, let alone smaller communities in northeast Iowa where Walker was likely stronger due to the proximity of Wisconsin to that part of the state. The last time Cruz held an actual campaign event in the area was April 1st. Bush has yet to really campaign aggressively in Iowa, but his campaign has done a better job than Rubio and Cruz in getting around the state.

Obviously, I was flat wrong, except for that bit about crusades. More on that in a moment. I picked the following as the first five Republicans to exit the race: Jim Gilmore, George Pataki, Lindsey Graham, Rick Santorum and Bobby Jindal. What I failed to realize was the nature of the different campaigns that are out there -- whether successful or not. There are serious politicians running for president who care about their future in politics, and then there are others who either already have a secure political future or have no political future whatsoever. In either of those last two cases, calculations about future political careers don't really apply to the decision to get out of an unwinnable contest. In both cases -- secure political future or no political future -- there's not much to lose by staying in, to put it another way.

Even with all the money pouring into politics after the Citizens United case, there is still supposed to be a dividing line between actual campaign organizations and super PACs. There are some things that super PACs are not allowed to pay for -- although even these limits are going to be tested in this campaign by various candidates. Even so, things like renting an office, paying staff who schedule appearances and plan the campaign, traveling to and from those appearances and all the other mundane nuts-and-bolts costs of campaigning absolutely must be paid for by the official campaign and not super PACs. This is why even with millions in a super PAC's bank account, Rick Perry and Scott Walker found it increasingly hard to pay their staff.

This only matters, of course, if a candidate is running a serious campaign for the presidency. It absolutely does not matter for candidates who never had a chance in the first place. If you're running just to see your name on the ballot, then it is irrelevant whether you even have any campaign appearances or staff. Likewise, if you're running on some personal crusade for an individual issue, you are likely not going to be stopped by having no money -- your cause is so great, you'll keep going no matter what happens, because you see the issue as larger than yourself.

With this in mind, let's try to predict who could leave the race next. To do so, I'm first going to divide the candidates up into three groups: vanity campaigns, crusaders and serious candidates. On that last one, by "serious" I mean the attitude of the candidate, and not how popular or successful any particular campaign currently is (just to be clear).

No more angry Bobby Jindal to kick around now, he's suspending his campaign. This is potentially good news for Huck, especially in Iowa where Jindal was polling around 5%.