For the republicans, this has been a weird election. For most of the race, the leaders have all been rebel candidates deeply unacceptable to the party establishment–Trump, Cruz, Carson–and with just a couple weeks to go until the Iowa caucuses, there’s no sign of this changing. If you’d asked me in the summer, I would have told you that sure, a few extremely kooky republican candidates might spend a little time making ephemeral runs in first place, but sooner or later an establishment candidate has to win out, just like Mitt Romney did in 2012 and John McCain did in 2008. Herman Cain had his month in the sun, but no one ever took him seriously, right? Sooner or later everyone converges around a Jeb Bush. It looks like my summer prediction isn’t going to come true, and like any good politics PhD student, that has me wondering what I got wrong. Over the past month I’ve been pondering this, and I think I’ve figured it out.

One of the reasons I was so inclined to think that someone like Jeb! would win in the end is that back in 2012, I was certain one of the rebels was going to break through, but none of them ever did. In particular, I thought Rick Perry might end up the nominee. When Romney won, I assumed that I was totally mistaken and that republican voters were never all that serious about nominating a kook in the first place. But what if I wasn’t so far off the mark in 2012? What if the republicans came much closer to nominating a kook that year than I believed?

So I took the 2012 republican field and split them into two camps–establishment and rebel. The establishment camp consisted of conventional republicans favored by party elites who stood decent chances of winning in the general election, while the rebel camp consisted of Tea Party republicans and libertarians with limited general election appeal. For 2012, the establishment republicans are Romney, Giuliani, and Jon Huntsman. The rebels are Newt Gingrich, Ron Paul, Michelle Bachmann, Herman Cain, Rick Perry, and Rick Santorum. I used Huffington Post‘s poll average for the 2012 election to calculate how the establishment candidates were doing relative to the rebels throughout the primary race. Here’s what I found:

The rebels led the whole way–mostly by 20 points or more. Yet they lost–Romney was the nominee. Now, I did this same thing with the 2016 republican slate. I included Bush, Rubio, Walker, Christie, Kasich, Fiorina, Pataki, Graham, and Gilmore on my establishment slate and Trump, Cruz, Carson, Paul, Huckabee, Jindal, and Santorum among my rebels. Here’s how the establishment and the rebels are doing in 2016:

As you can see, the rebels are ahead again by 20 points or more. The only real difference between this year and 2012 is that the rebel lead hasn’t reduced from 30 to 20 starting in December. This becomes evident when you put both charts together:

What this suggests is that baseline support within the party for establishment and rebel candidates is more or less the same now as it was in 2012, and in both these cases the rebels had the heavy electoral advantage. So the real question is not why Jeb! can’t win, but why Romney could.

The answer is already here in the information I’ve given you. It’s the number of establishment and rebel candidates. Recall that in 2012, there were only three establishment candidates. Romney, who consistently enjoyed 20-30% of the vote, Giuliani, who dropped out early, and Huntsman, who never climbed out of the low single digits. Effectively, if you wanted to support an establishment candidate, you had no choice but to pick Romney. So the establishment support was quickly consolidated around him. On the rebel side, there were six candidates and each one of them enjoyed significant support at varying points in the race. Here’s what the Huff Po poll average looks like for 2012:

See how none of the rebel candidates manages to get a clean shot at Romney head to head? Throughout the entire race, Ron Paul siphons 8-12 points away from the leading challenger. During Rick Perry’s run in first, he had Bachmann, Cain, and Gingrich taking another 10 points or so. During Cain’s run in first, he was hurt both by a diminishing Perry and a rising Gingrich. When Gingrich was in first, he was hurt by a diminishing Cain and a rising Santorum. When Santorum was in first, he had to deal with Gingrich, who continued to hang around with 10-15 points. So each leading rebel candidate’s vote share was depressed well below its potential. A rebel who ran against Romney alone should have managed over 50%. What happened is that as the rebel candidates continued to fight it out to determine who would get to be the bearer of all those rebel votes, Romney continued to win primaries and caucuses, often with just 30-40% of the vote.

In today’s race, the establishment has failed to consolidate around a single candidate, so no single establishment republican has inherited Romney’s vote share. A single establishment candidate could probably have 25-30% right now–not enough to be ahead of Trump, but enough to beat him in a lot of moderate states and dissolve his aura of invincibility. Instead, there are half a dozen establishment candidates splitting the vote. The rebel vote is split as well but because the rebel vote is much larger the rebel leader is necessarily going to command more support than the establishment leader. This gives us the scenario we’re in now, where the 1st and 2nd place national candidates are both rebels with Rubio in 3rd:

So when I thought the Republican Party was going to be captured by its fringe in 2012, I wasn’t wrong on the fundamentals. Romney was incredibly lucky that he had no credible establishment challengers while the rebels were fractured. My mistake this summer was to assume that because Romney won, that meant that I had to have been mistaken about the underlying structure. It might have been a defensible mistake to make when Bush had 20%, but even then I should have been aware of how precarious the situation was. If I had paid closer attention to the data from 2012, it should have been clear to me that it was only a matter of time before the Republican Party was captured by its fringe in a presidential election, and that this would happen as soon as the establishment vote split. And in the meantime, having to fight off the rebels was crippling republican general election campaigns. Even Romney was forced to pull too far to the right to compete effectively in the general election, according to the Republican Party’s own post-election research, and in 2008 John McCain was forced to nominate Sarah Palin to appease the rebellious republican base. Unless the establishment coalesces around a single candidate very rapidly, it is now a near certainty that a rebel candidate will be the nominee, and that means it is a near certainty that the democratic candidate will win in 2016.