Des Moines, Iowa • I’ve heard Joe Biden speak twice in Iowa over recent days. Both times, I walked away barely able to remember a single issue he mentioned. I had to check my notes. Ah, yes, guns: He touched on that. Climate change, too. That flitted by.

But Biden’s closing argument in Iowa, whose caucuses Monday night provide the first meaningful measure of the traction that the various Democratic candidates have found, doesn’t hinge on any of those. That’s because his bid for his party’s presidential nomination doesn’t, either. Maybe more than any campaign I’ve observed over the past quarter century, it’s about character — his and the country’s.

It’s about honesty, decency, empathy, humanity. For reasons we’ll be plumbing for many years to come, America in 2016 elected a president bereft of those traits, and the country ever since has been in a moral free fall. So Biden is waging a “battle for the soul of the nation.” It says so in big letters on the side of the bus that has been carrying him through this state. He’s running to reconnect America with the best of itself.

At a crowded, spirited rally here in Des Moines late Sunday afternoon, he recited and railed against examples of Donald Trump’s cruelty, his voice thick with disgust.

Speaking to hundreds of voters in Waukee, Iowa, on Thursday morning, he asked: “Does it matter if a president has no moral compass?” It was a rhetorical question and the core of his message.

It was also powerful, much more so than I expected.

In debates and television interviews since he formally entered the race for the Democratic nomination last April, Biden, 77, has been unimpressive, his energy palpably diminished, his sentences wobbling toward some destination other than the initially intended one.

On the stump, though, he has vigor. He has something else, too: an aura of overarching goodness that’s a tonic in the context of Donald Trump. I found myself quaffing it greedily, parched from the past few weeks, when Trump’s Senate trial confirmed how unbound the president is and how completely Republican lawmakers have surrendered their integrity to him.

Will Iowans find Biden as consoling as I do? Can “consoling” drive people to the polls?

Recent voter surveys give the edge in the caucuses to Bernie Sanders, who also leads in New Hampshire, could wind up winning the first two Democratic contests and has a profoundly different vibe. He’s about fighting fire with fire. Biden is about dousing the flames with compassion. And for many voters, that’s “a nostalgia act whose well-worn slogans about middle-class uplift and national unity are out of sync in this season of outrage,” as Molly Ball wrote in Time magazine last week. Biden was on the cover.

As I pinged around Iowa and heard speeches by all four leading candidates (Sanders, Biden, Elizabeth Warren and Pete Buttigieg), I realized that there are three R’s of this Democratic primary.

There’s revolution, which is what Sanders expressly urges — “revolution” is his mantra — and which Warren less bluntly promotes, calling for “big structural change” and vowing to “take our government back.”

There’s rejuvenation: Buttigieg, 38, leans on the fact that his three main rivals are all 70 or older to stress the importance of a fresh set of eyes and the need to give a new generation of politicians a chance.

And there’s restoration. That’s Biden, the country’s vice president from January 2009 to January 2017. He weaves many references to President Barack Obama into his remarks, mentioning “our administration,” and in a 60-second video that he shows at the start of his events, Obama’s face appears before his does and pops up another two times.

What Biden is promising, though, isn’t so much a return of personnel or policies as of propriety. He wants to make America normal again. He told the Waukee crowd that in Trump’s world, “Up is down, lies are the truth, allies are enemies. Everything is through the looking glass.” He’s going to rescue us from that wicked wonderland. And he’s going to do it by being a really nice guy.

Let Sanders go point by point through the virtues of “Medicare for All.” Let Warren illuminate the intricacies of her anti-corruption plan. Biden is fuzzier and gooier than that — by design. You’re supposed to leave a Sanders or Warren rally suffused with righteous anger. You leave a Biden rally sort of misty and choked up.

His event in Waukee was arguably most memorable for remarks by Tom Vilsack, the former governor of Iowa, and his wife, Christie, about how loving and supportive Biden had been to their family three years ago, when their 6-year-old granddaughter died. Biden, they said, knows about loss, having buried two of his own children, along with his first wife. It has humbled him. Seasoned him. He senses sorrow and does what he can to soothe it.

They made him sound like an angel and maybe I’m also making him sound that way. He’s not. His record as a senator for almost four decades is full of questionable judgment calls, messy compromises, expedient affiliations. There’s gunk there, if not in the places where Trump insisted it was.

But there’s also enough merit for him to make his curious and curiously compelling pitch. It’s a mature pitch, too, implicitly acknowledging that none of the grand plans that the Democratic candidates describe are likely to be enacted as is. What voters should choose, then, is someone with values and a temperament they trust.

That’s Nancy Bobo’s thinking. Bobo, 67, showed up to hear Biden in Waukee and said that she’d caucus for him Monday night. “Trump has empowered people to be hateful,” she told me, adding that the answer to that is a leader who’s “decent, kind and loving.” Biden checks those boxes for her. Biden makes her feel good about things.

Does that make him the Democrat most likely to beat Trump, which matters so much more than anything else? Got me. We’re all just lobbing guesses, crossing our fingers and holding our breath.

But I do think that the potency of Biden’s appeal as the smile to Trump’s scowl, the calm to his storm and the rectitude to his dissoluteness may be underrated.

Trump has a cameo in that 60-second video, which shows him in mid-scream. It ends with an image of the Oval Office and these words: “Character matters — maybe here more than anywhere.” Every Democratic candidate would agree with that. Only Biden is putting all of his chips there.

Frank Bruni (CREDIT: Earl Wilson/The New York Times)

Frank Bruni is an Op-Ed columnist for The New York Times.