In an election where the seven battleground states are all polling within a percentage point or two, 50-50 is the only responsible forecast. Since the debate between Kamala Harris and Donald Trump, that is more or less exactly where my model has had it.

The people whose gut tells them Mr. Trump will win frequently invoke the notion of “shy Trump voters.” The theory, adopted from the term “shy Tories” for the tendency of British polls to underestimate Conservatives, is that people do not want to admit to voting for conservative parties because of the social stigma attached to them.