How will undecided Americans choose between Kamala Harris and Donald Trump — or decide to vote for neither — in the final six weeks of the campaign?

To better understand these voters’ thinking, my colleagues and I added an open-ended question to the most recent Times/Siena College poll in which we asked people to name their biggest concern about each candidate. In today’s newsletter, I’ll explain the results.

Trump’s temperament

We define swing voters as the roughly 18 percent of likely voters who say they haven’t yet made a firm decision. Some describe themselves as undecided, while others say they’re leaning toward one candidate but open to changing their mind.

(All the numbers in today’s newsletter come from a poll of three swing states — Arizona, Georgia and North Carolina. But I’ve analyzed a similar question in a nationwide poll conducted by YouGov and The Economist, and the themes were similar.)

Swing voters’ biggest concern about Trump, by far, is his temperament. “He’s unwilling to admit that he’s been wrong about anything,” said a white woman under age 30 who has a bachelor’s degree. A middle-aged Hispanic woman without a degree said, “My biggest concern is about the way he handles himself.”

Many of the responses were withering. People called him — and I’m using their exact words here — emotional, impulsive, reckless, unstable, unhinged, childish, arrogant, disrespectful, narcissistic, selfish, rude, chaotic and erratic. Overall, 35 percent of swing voters said that his personality was their biggest concern about him: