Having at started with a clustered 17-person field, the 2016 GOP primary has seen candidates drop out of the race in four of the past six months, with each departure reshaping the prospects for election outcomes and the nomination. The winnowing process in 2015-16 has accordingly been much more prolonged than in the past, making for a very different race–and distribution of support–with a field of 15 candidates than a field of three or five. Most importantly, amid the wide ideological range that characterizes the modern day Republican Party, support behind a dropped-out candidate won’t be equally distributed across all the remaining ones, or go to the frontrunner necessarily, but instead maybe gravitate towards the most ideologically similar one remaining.
Regardless, three candidates have now dropped out after Iowa, three after New Hampshire, and one after South Carolina. A few more of the remaining pool are bound to exit as well, especially as the pressure to find an alternative to Donald Trump–for which the GOP establishment is quickly running out of time–ramps up as we approach Super Tuesday.
In that vein, I looked back at past GOP candidate dropouts during this election cycle to see how they affected the race. In the chart below, I average the polls–for each five candidates remaining–for the week before a past contender dropped out, the week after that decision, and what the change was. The bottom row shows the average effect of each dropout on the five candidates’ support.
A few notes: 1) Rick Santorum and Rand Paul dropped out on the same day, so they’re included in the same set of three rows; the same goes for Carly Fiorina and Chris Christie, whose pre- and post- dropout weeks overlap. 2) No polling has come out after Jeb Bush’s exit, so he’s not included, and neither is Jim Gilmore, for what I’ll call too little polling about him. 3) The averages come from polls entirely before or after the dropout date. 4) The top of the chart of course doesn’t include other candidates who likely benefited from early dropouts, but dropped out later on.
First off, several potential confounds abound. Namely, the election results in February could have greater effects on candidate support rather than the redistribution of other support once tied to now dropped-out candidates. Other events might also have exerted greater influence, and perhaps account for the larger net changes seen above. Nevertheless, the short time spans involved here should capture the immediate changes in the race–and not be as influenced by other significant events. The averages in particular offer the clearest answer to the question at hand.
Across the eight different points at which a GOP candidate or two has exited the race, Marco Rubio has benefited the most from fellow contenders’ departures–but not by too much, as is the case with the other four remaining candidates. Especially as of late, he began to receiver larger bumps, but that stopped after the New Hampshire election. While he has risen in public support since September, the type of Republican party coalescence around one candidate needed for him to win–and which occurs so often in primaries–has not been that evident in where a dropped out candidate’s support has gone. That coalescence seemed likely earlier on in the election cycle, and now seems more definitive–the rank and file of the party now just have to follow suit.
Ben Carson experienced the largest polling percentage point loss, but that comes amid a broader decline. Next is Trump in terms of losses, but he still stays in the 30s range throughout this time period–as expected for a contender with a high floor but low ceiling.
Overall, dropouts have not made that much of an effect on the remaining contenders’ support. That, however, will certainly change in the near future, as more candidates will drop out with higher polling percentages and leave a smaller field to receive their support–that begins in earnest with Bush’s exit.