Day After Debate, the Campaign’s Focus Moves to Arizona

“How many more have to go under?” Mr. Biden said, his voice echoing in the union hall that was largely empty because of social distancing. “How many more dreams have to be extinguished because this president threw in the towel? If I were a playwright and writing a play, there’s isn’t a single solitary outfit on Broadway that would take it, because it sounds like ridiculous fiction.”

Acknowledging the support of Ms. McCain, who endorsed Mr. Biden last month, the former vice president recalled the 2018 eulogy for Mr. McCain that he delivered in Phoenix.

“We used to argue like hell,” Mr. Biden said of his relationship with his longtime Senate colleague, a Republican. “We were like two brothers — we’d fight like hell, but we always, always, always ended up together. And that’s how it used to be.”

In an earlier political day, it might have been unusual for three of the four people on the two major parties’ tickets to be stumping in Arizona less than a month before the election.

A Democrat has carried this state just once in recent history — Bill Clinton in his sweeping 1996 re-election — but a growing Hispanic population and suburban voters alienated by Mr. Trump have made Arizona more competitive. Senator Kyrsten Sinema, a Democrat, won her seat in 2018, and Democrats are favored to claim the state’s other Senate seat next month.

Introducing Mr. Biden, Ms. Harris plugged her party’s candidate for that seat. “Let’s send Mark Kelly to the Senate,” she said, referring to the former astronaut and first-time candidate who is challenging Senator Martha McSally.

The rare joint campaign-trail appearance by the Democratic ticket occurred a day after Ms. Harris’s debate outing, which is likely to be her most prominent appearance before Election Day. Mr. Biden praised her performance, saying she was “like a younger sister.”

“I tell you what, you got to give me great credit for knowing how to pick ’em, right?” he said.

As he neared the end of his address, Mr. Biden pleaded with Arizonans to vote.

“Early voting has already begun,” he said. And noting that mail-in ballots, which many voters here are accustomed to casting, would also soon arrive, he added: “The best thing you can do is return your ballot quickly. Don’t risk delays. Return that mail-in ballot as soon as you can.”