Sheri Berman The 2020 election was the most traumatic and dangerous in modern American history. Its legitimacy was indefensibly questioned by Republican elites and voters, helping to motivate an insurrection designed to block its outcome. What explains the diametrically opposed narratives of the 2020 election advanced by Republicans and Democrats and the broader democratic dysfunction of which this is a manifestation? One common explanation focuses on ‘hyper-partisanship’ and polarisation. In the decades following World War II in the United States, party identification and voter loyalty were relatively weak, Democratic and Republican voters and elites relatively ideologically heterogenous, and vote-switching or split-ticket voting (choosing different parties in national and state-level elections) relatively common. By the early 21st century, however, the situation had changed dramatically: partisan identities had become deeply felt and entrenched, Democratic and Republican elites and voters had become more ideologically homogenous and distinct from each other, and vote-switching and split-ticketing voting had become relatively uncommon.