That night, Ms. Gabbard attends a dinner party in a field to celebrate the installation of the solar panels, an event that features a large cohort from Los Angeles, including the actresses Frances Fisher and Shailene Woodley.

Her sister is there, and seems to have recovered from the fall, though she says she is suffering from memory loss.

Ms. Gabbard gets onstage to give a speech. She talks for about four minutes, barely mentioning her policies or even the campaign itself.

Ms. Gabbard says she is driven by the feeling that death could come at any moment, which she realized at age 10 but which became more intense in Iraq.

“My first deployment was at the height of the war in 2005. We were 40 miles north of Baghdad. And there was a huge sign by one of the main gates that just read: ‘Is today the day?’” she says. “It was such a stark reminder that my time could come at any moment. That any day could be my last.”

She is not sure who put the sign up or why. But it was this message of potentially imminent doom that she wanted to leave the audience with at the second Democratic debate.

“As we stand here tonight,” she told the crowd, “there are thousands of nuclear missiles pointing right at us, and if we were to get an attack, we would have 30 minutes, 30 minutes, before we were hit.”