There is a widespread inclination to treat the primaries as an entirely separate phenomenon from the general election. In a sense, this is wholly justified for reasons empirical and theoretical. As the fivethirtyeight.com post covered the empirical aspects of this justification, I will offer the theoretical: the choices facing the voters are different in the primaries and the general. People choose to spend their time on voting for a reason, and that reason is supplied by the candidates and the circumstances under which the election takes place, even if the voters themselves remain the same. If the candidates and the circumstances change, there is no reason to expect that the same voters would continue to participate.
This is hardly a new observation: one reason Gary Hart was thought to be the more formidable candidate in 1984, at least until the scandal involving Donna Rice came out–and changed the circumstances of the election, so to speak–was the recognition that he activated a different set of voters from Walter Mondale and many if not most of those voters were expected to remain in support of Hart candidacy in the general but not necessarily Mondale. The fall of Hart candidacy, of course, ensured that this could not be evaluated, of course, and furthermore underscores the difficulties of evaluating the impact of “unusual” candidates on turnout by different demographics: candidates who try to draw on “unusual voters” to win the nomination rarely succeed in winning the nomination.
On top of these, we just don’t have that many presidential elections to draw data from and analyze to the satisfaction of statistical significance. This limits us to two responses: we can refuse to believe the data that we have since they are not close to being conclusive, or we can try to learn what we can from the data, but with the recognition that the data is not very good and the conclusions drawn from them largely unreliable. Science demands that we should stick to the former, if we want to gain good, reliable insights. But we are trying to gain some insights, not necessarily good and reliable ones. With appropriate caveats, I see little reason not to.
The search for a historical analogue to 2016 brings us to 1980: the primary turnout was high on the Republican side, due to many voters enthused by Ronald Reagan as well as by many opposed to him. Indeed, the #NeverReagan movement within the Republican Party gained enough support that John Anderson ran a third party candidacy. Reagan was considered, despite his tenure as governor of California, considered a political incompetent who did not know what he was doing and an out of touch extremist who might bring the Republican Party by bleeding disenchanted voters, while he claimed that he was drawing new voters in. It is premature to conclude that Trump would necessarily win because he is like Reagan, for the opposition to Reagan within the Republican Party was nowhere as strong as Trump’s today. Reagan’s support was so large than he carried so many primaries by huge margins after a few hiccups in the early going. It certainly helped that, for all his non-mainstream appeal, he was also an experienced electoral politician who did, after all, nearly derail a sitting president’s (Gerald Ford’s) campaign in 1976 in addition to his time as a large state’s two-term governor. Trump, in contrast, seems to have hit a hard ceiling around 40-45% even within the Republican Party.
Reagan, presumably, would have activated similar kinds of demographics in the early primaries in both 1976 and 1980. In 1976, with Ford, rather than Reagan as the nominee, did these voters stay home, while, in 1980, with Reagan at the top of the ticket, did the same voters stay onboard? The demographics of Reagan and Ford electorates do seem different enough, with Ford’s being much more upscale in terms of income and more “conservative” (in practice, this just means that Reagan drew a lot more voters who did not fit liberal-conservative scale neatly, not that he drew necessarily “moderate” voters–the same reason Trump draws many “moderate” voters), although Reagan’s coalition in 1980 does not look quite like his 1984 coalition. Since the exit polls themselves from these years are, unfortunately inaccessible for me at this time, the more detailed analysis will have to wait. But they suggest that some aspects of the general election coalition may be predictable from the primary results: IF Reagan’s early success was dependent on blue collar, apolitical voters, they seem to have carried over to his general election coalition. (It is also worth noting that head-to-head matchups in 1980 showed Carter defeating Reagan handily until August, at least)
After Reagan, there was another primary presidential candidate who drew out unusual voters and won primaries unexpectedly riding on them, and mostly kept them in the general–Barak Obama in 2008. Other than these, we just don’t have primary polling data that is readily available (Roper Center’s data goes back only to 1976).
So, two data points, from two very unusual presidential candidates, Reagan in 1980 and Obama in 2008, that MIGHT, upon further analysis, suggest that who turns out in primaries might give us useful clues, although not definite guidance, about who would turn up in the general election–although the overall turnout might well be a red herring. In 2016, we have another strange election brewing, with another candidate drawing out strange voters. The information we have is almost completely unreliable and I would not suggest for a minute that there is much that is reliable here. However, we also know that where the data is plentiful, there is no useful insight to be had. So between reliable but useless information and totally unreliable but perhaps insightful information, what shall it be?