Skip to main content

Do Bitter Primaries Hurt Presidential Candidates?

Decades of research suggests that one candidate will suffer most from 2016’s bloody primary season.

By Jared Keller


(Photo: Scott Olson/Getty Images)

The end is nigh.

After months of “vulgar and divisive” rhetoric, one of the most polarizing and stupefying primary seasons in recent memory is drawing to a close. Donald Trump clinched the Republican presidential nomination last week after steamrolling a gaggle of incompetent Beltway power players in a bloody, vile contest that left the Grand Old Party in disarray. Former Secretary of State Hillary Clinton, though the presumptive Democratic nominee since the moment she announced her candidacy more than a year ago, has seen her presidential bid subject to a prolonged primary battle against Senator Bernie Sanders. With party conventions on the horizon, both Trump and Clinton are likely catching their breath before the main event.

There’s one problem: America hates both Clinton and Trump. Both face the least favorable ratings since 1984, according to an ABC/Washington Post poll. This isn’t just because the electorate is the most politically polarized it’s been in decades. “If Trump and Clinton’s strongly unfavorable ratings were simply a byproduct of polarized politics, you’d expect them to have high ‘strongly favorable’ ratings too,” explains FiveThirtyEight’s Harry Enten. “They don’t.”

Why are Trump and Clinton facing such a tough general election? There’s one major possibility: The bloody, divisive primaries have doomed both campaigns to a particularly challenging general election. The Trump and Clinton campaigns may have won their primary battles, but at the cost of the war. That’s the conclusion of recent research by the University of Oxford’s Alexander Fouirnaies and Stanford University’s Andy Hall, which examined all United States House and Senate elections from 1896 to 2012 (as well as data on primaries, runoffs, and general elections for state legislatures). Their analysis suggests that particularly tough races — mainly, those ending in runoffs — tend to decrease a party’s vote share by six to nine percentage points on average in a general election, decreasing the probability of a general election victory by an average of 21 percentage points.

The bloody, divisive primaries have doomed both campaigns to a particularly challenging general election.

While the majority of political science research has focused on legislative (both state and federal) and gubernatorial races, the impact certainly translates to presidential elections. Observing that runoff primaries as a measure of divisiveness tend to actually help candidates in state legislative races, Hall and Fouirnaies concluded that electoral salience — the relative importance and impact of a vote on different policy areas — is a major determinant of the impact of divisiveness. Races that garner far more attention and scrutiny from both voters and the media (House and Senate elections more than state legislative races, even though the latter have a more substantive impact on the daily lives of taxpayers) tend to be more profoundly shaped by intra-party conflict, a trend that, to Hall and Fouirnaise, translates to the presidential contest. “Given that the effects are increasingly negative the more salient the office,” Hall told Vox, “it suggests there would be big penalty for president.”

Decades of political science scholarship reveals that bitter primaries appear to be the least damaging for insurgent, low-expectation outsider Republicans — and most for incumbent Democrats. A 1980 study in American Political Research and a 1984 study in the Journal of Politics both found that the negative effects of contested primaries seem more pronounced for Democrats than Republicans. That’s troubling news for Clinton supporters, especially because, according to a 1987 analysis in the American Journal of Political Science, in the event that one party endures a particularly schismatic primary season while its opposition candidate goes relatively uncontested (which is now the case, as Clinton continues to battle Sanders while Trump waits calmly in the wings), the divided party suffers at the ballot box. A 2011 examination in Legislative Studies Quarterly found that expectations of victory shape the impact of hostile primaries on general elections: Hostile primaries mainly hurt incumbents who seem to have a race locked down, but give “outsider” challengers (i.e. Trump) momentum under the banner of a dark horse electoral insurgency.

Despite predictions that Trump would never, ever secure the GOP nomination, he has consistently polled higher than his milquetoast challengers, thanks in part to a crafty narrative around his outsider status. By contrast, Clinton’s been forced to justify her (and her husband’s) political legacy to both the stubborn, intransigent Sanders campaign and an untrusting public.

The result: A former secretary of state is in a near dead heat with a the former host of The Apprentice. “No doubt, it is tempting, too, to extrapolate these results and use them to predict the current presidential election,” Fouirnaies and Hall write on the 2016 presidential contest. “Clearly, the Republican primary has been historically divisive, and the whole world has been watching. As such, we would expect a substantial penalty to the party in the upcoming general election. On the other hand — and conveniently this allows us to hedge our bets a little — the Democratic primary has also been quite competitive.”

The run-up to the party conventions has proven a nail-biter for what should be a slam-dunk general election for Democrats. That the GOP has embraced party unity faster than Democrats matters, and Sanders’ continued feud with the Democratic National Committee and other organs of the Democratic establishment could continue to undermine Clinton in more damaging ways than the Republican field ever had to endure.