INTRODUCTION Understanding the Unprecedented 2016 Campaign: Two Historical Candidacies Yield an Unexpected Result Benjamin R. Warner and Dianne G. Bystrom Four days after the 2016 presidential election, Sam Wang, a professor of neu- roscience at Princeton University and publisher of the Princeton Election Con- sortium site, ate a bug on national television. On November 7, the day before the 2016 U.S. presidential election, Wired published a lengthy article in which they declared that Wang had replaced FiveThirtyEight’s Nate Silver as the true election data hero (Nesbit, 2016). How did Wang unseat the reigning king of political prognostication? It was the bold certainty with which he forecast the election—Wang declared Hillary Clinton the victor on October 18, more than three weeks before the 2016 election. As explained in the November 7 profile, “Wang has been the intrepid election data explorer furthest out this election cycle, never once wavering from his certainty of a Clinton win” (Nesbit, 2016, para. 9). When the dust settled on November 8 and Donald Trump was declared the 45th president of the United States, election forecasters were left