On the other side of the spectrum are two “tribes” of Trump voters, roughly evenly divided, which together make up another quarter of the electorate. One of these groups (12 percent) is the Trump base — the “Make America Great Again” crowd that attends his rallies and idolizes his brand of conservative populism. The other (14 percent) consists of traditional Republicans with less edgy views on issues ranging from trade to immigration to race relations.

A fourth group, which Della Volpe has dubbed “The Detached,” is even harder to peg. This segment is the youngest of the five, and the most male. They tend to be disillusioned, even disgusted, by party politics, and represent 24 percent of registered voters in the United States.

A fifth cohort, the “Independent Blues,” is the most pivotal group. In 2016 they cast their ballots for Hillary Clinton by a 12-percentage-point margin, and their skepticism toward Republicans has only grown in the ensuing two years. Just 16 percent of them say there is a strong likelihood they’ll vote for Donald Trump in 2020. By a margin of 47 percent to 28 percent they express a preference for a Democratic-controlled Congress.