Every four years conservatives invoke the Buckley Rule in debating who they should support for the GOP nomination. William Buckley, a leading light in the conservative movement, admonished conservatives to coalesce behind the “rightwardmost viable candidate.” Buckley meant that movement conservatives should prudently weigh considerations both of ideology and electability to identify the most conservative candidate that can keep the Democratic nominee out of the White House.
For conservatives in 2016, who is this candidate? The answer as of right now may surprise you: Jeb Bush.
Here’s how this logic works. Obviously, conservative voters want a conservative candidate. However, as we noted in an earlier post, strongly ideological candidates are punished at the polls. So nominating a strong conservative might actually backfire if it helps elect a Democratic president.
A strong conservative voter has to take into account three things. The first is how conservative the various Republican candidates are.
The second is the identity of the Democratic nominee. If the Democrats nominate a strong liberal, like Sanders, Republicans can nominate a strong conservative without fearing that it would backfire (for background, see this research). But at this moment, Republicans should arguably assume that Hillary Rodham Clinton will be the likely Democratic nominee.
The third is how electability is associated with Republican candidates at different points along the ideological spectrum. This is Buckley’s viability consideration.
The graph below illustrates how to evaluate the trade-off between electability and conservatism. The horizontal axis arrays candidates according to their ideological conservatism, as measured by Stanford political scientist Adam Bonica. To calculate the expected outcome of the 2016 election, we draw on data about viability from prediction markets, which gauge the odds of various candidates winning the November election. As we’ve noted before, the collective wisdom of political science scholarship and prediction markets is that more moderate candidates are more electable.
(If you want the math behind the plot, here it is: Prob(GOP Nominee Wins Presidency | Ideology of GOP Nominee) * GOP Nominee Ideology + Prob(Democratic Nominee Wins Presidency | Ideology of Democratic Nominee) * Democratic Nominee Ideology.)
Graph by Matthew Atkinson and Darin DeWitt
Here’s the intuition. Say that a conservative voter would like a Ted Cruz presidency. But if Cruz is unlikely to keep Clinton out of the White House, then a Cruz nomination would not be associated with a conservative outcome. By contrast, Christie’s electability is likely to keep Clinton out of the White House, but Christie’s moderation means that he wouldn’t maximize expected conservatism either.
Of the leading candidates, it’s actually Jeb Bush that produces the best possibility for a conservative result.
This isn’t to say that Bush will win the nomination, of course. Prediction markets actually see that possibility as less likely than it was a few months ago.
It’s just to say that if conservatives want a conservative president, they will need to get behind a candidate who otherwise might seem “too moderate.”
Matthew Atkinson is a Visiting Assistant Professor of Political Science at Miami University. Darin DeWitt is an Assistant Professor of Political Science at California State University, Long Beach.