The original formulation of the beer question invites the question of why voters would care so much about something that is exceedingly unlikely to happen. If you invert it, however, voters start to look a lot less irrational. After all, they can’t foresee all the decisions politicians will need to make once in office, and have few ways of holding them accountable if they don’t follow through on their promises. So they need to estimate which politicians are most likely to understand and advance their interests.

A candidate’s attitudes toward “people like me” thus become a powerful heuristic. If a candidate generally likes people like me, then it seems plausible that he will look out for my interests in a wide range of scenarios. If he dislikes people like me—if he would hate sharing a beer with me, and secretly thinks I’m trash—then he is far more likely to sell me out.

The inverted beer test provides an explanation for why Coakley’s gaffe was so harmful: A politician who finds the idea of spending time with Red Sox fans unpleasant is not going to balk at selling them out. It also explains why Gordon Brown calling an elderly lady “bigoted” in 2010, or Hillary Clinton describing some Donald Trump voters as a “basket of deplorables” in 2016, resonated: It seemingly confirmed many voters’ suspicions that they are elitists who look down on “ordinary” people.

Because pollsters have, to my knowledge, never directly asked voters whether they feel that a candidate would like to share a beer with them, I can’t offer direct proof for my hypothesis. But likedability, rather than likability, does help to make sense of something else that has puzzled many pundits of late: Joe Biden’s stable lead in the Democratic primary.

Since his earliest days in politics, Biden has yearned to make a connection with every person in the room. As Richard Ben Cramer described in What It Takes, the classic account of the 1988 presidential campaign, Biden would refuse to move on from an event until he felt that he had made “the connect” with every single person who had come to see him.

In a more recent profile that is, on the whole, critical of Biden, New York magazine’s Olivia Nuzzi describes his love of people in strikingly similar terms:

He really does connect with every living being this way, talking about their jobs or their health care as he listens, sometimes crying with them, whispering in their ears, taking their phone numbers and promising to call them. He does, in fact, do that. Everybody is Joe Biden’s long-lost friend. Every baby is Joe Biden’s long-lost child. A little girl in Iowa City called him her uncle Joe. On the Fourth of July in the town of Independence, he took off, running through the parade like a dingo with somebody’s newborn. As hard as it might be to believe that anything in this realm could not be bullshit, it’s simply true that this isn’t.

Even Biden’s insistence that he would be willing to work with Republicans—which has been panned by pundits, who dismiss this aspiration as antiquated—takes on a somewhat different complexion from this vantage point. By emphasizing that Republicans are too extreme and partisan to come to the negotiating table, other candidates implicitly impugn the character of anybody who has voted for them. This includes not only those voters who are so disappointed with Donald Trump that they are open to voting for somebody like Biden in 2020, but also many spouses, siblings, or parents of those who usually vote Democrat.