They said they had watched with dismay as the crisis mounted in recent days, and expressed confusion about President Trump’s comments on the virus.

“I am deeply worried about how unprepared we are for this,” Mr. Devenport said, while adding that he had found inspiration among his friends.

He said he felt as if they were looking out for one another in new ways, such as texting when they are out shopping to ask, “Can I pick anything up for you?”

Voting, he said, is a kind of extension of that community, a way he could act when so many feel helpless. As voters, they could practice social distancing even as they attempted to knit society back together.

“We don’t have enough people out there talking the truth and speaking about reality,” he said. “We shouldn’t have to be this way.”

Sara Miller, 53, a teacher at a Catholic school, had gone to a Costco in Phoenix on Friday morning to try to buy food for a weekend dinner party. She walked out empty-handed after she saw the lines and the picked-over aisles.

“What we’re seeing now is mob mentality and someone needs to talk us out of that, get us out of that kind of thinking of every man for himself,” said Ms. Miller, a lifelong Democrat who mailed in her ballot for former Vice President Joseph R. Biden Jr. last week, in large part because she liked his demeanor.