They feel invested in this American presidential race, like no election before, and fret about its outcome — even if, for the most part, they don’t have a vote.

A current of helpless anxiety runs through hundreds of emails and Facebook posts from New York Times readers around the world since I arrived here in July to help cover the helter-skelter presidential election, now hurtling down its homestretch. Among foreigners, it boils down to a single question: How did it come to this?

“In one of the most mature democracies in the world, how does a campaign get so wild?” asked Manu Duggar, a Nepali living in Canada. “I’m afraid,” said Bernt Klein, a computer scientist in Germany.

Overwhelmingly, international readers say they are transfixed by the unorthodox candidacy of Donald J. Trump, the Republican candidate, and confounded by the strong emotions that Hillary Clinton evokes among many Americans, including Democrats.