Sanders-Trump voters illustrate multi-peak preferences on Down's traditional scale

It is estimated that somewhere between 6 and 12% of those who voted for Senator Bernie Sanders in the 2016 Democratic primary ended up voting for Donald Trump over Hillary Clinton in the 2016 general election. That number is large enough in several very close states that had this group voted for Clinton, they would have brought her over the top to win the election. This statistic is very baffling to many as Bernie Sanders certainly seems closer to Clinton in ideology and on the left-right spectrum Downs uses than he is to President Trump, who is on the opposite far end. Using that spectrum, these Sanders-Trump voters would illustrate multi peak preferences, meaning they prefer a candidate seemingly very different from their ideal preferences/candidate to one only slightly different. This violates the single-peaked preference assumption of Downs's model.

However, I propose a different spectrum for understanding this set of voters that would make their preferences single peaked once again and their choice to vote for Sanders and then Trump rational. That is, these voters didn't necessarily care about a candidate's ideological purity, but rather the extent to which they saw them as a change to the status quo in Washington. They preferred the candidate that they viewed as most likely to shake up the system (i.e. draining the swamp, not being beholden to the money of big business, etc). You can argue whether Bernie Sanders ranks higher than Donald Trump in that regard, but Trump undoubtedly ranks higher than Clinton, who essentially ran on the idea of continuing the Obama legacy and has been in government for decades. Thus once Bernie Sanders was out of the running, Trump was the next best choice for these voters who highly valued upending the political system. Those who supported Sanders in regards to their preference for leftist ideology, in turn, still voted for Clinton (or, in some cases, Jill Stein as a protest vote to push Clinton to the left).

The increasing number of and preference for populist, anti-establishment candidates suggests we may benefit from rethinking the traditional left-right spectrum to better understand voter preferences and behavior.