Martha C. Nussbaum is Ernst Freund distinguished service professor of law and ethics at the University of Chicago. Her most recent book is “The Monarchy of Fear: A Philosopher Looks at Our Political Crisis.”

On a subzero day in early March, I was the first to arrive at the immigration building in the Denver suburb of Centennial for the citizenship ceremony. To celebrate the big day for my son-in-law, originally from Germany, I had flown from Chicago. After going through building security, I sat contentedly in a sunny waiting room reading a dissertation chapter on Aristotle by a PhD student of mine, who recently announced that she is in the process of gender transition — the old and the new of America in a nutshell, I thought. People trickled in: individuals, families, my daughter’s boss at the animal rights NGO where she works as an attorney, then my daughter and son-in-law. He was so proud, dressed elegantly in a dark suit. Photos galore.

At 1 p.m., we were led upstairs to the ceremony room — first, the new almost-citizens with their paperwork (swearing that since the test they had committed no crimes, etc.), then the well-wishers. Many of the new citizens were single or otherwise without supporters. I talked to a woman who volunteers helping immigrants prepare for the test: She was there to support one of her students, a single young man.

It’s sometimes hard for academics to shed critical detachment and be heartfelt, but this ceremony didn’t strike a false note. Our emcee, a warm and gracious young woman, honored the countries of origin by asking the people from each to stand — 30 countries! There was a short film showing photos of immigration through the years, followed by the singing of the national anthem, then the oath of citizenship, read out solemnly. I was struck by the emphasis on service as well as privileges. (Quite a few of the families, I later recognized, are current or former members of the military.) Next, a video message from President Trump, totally restrained, scripted and appropriate. Then, one by one, our new citizens came up to get their certificates, accompanied by happy photo-ops, and the emcee’s mangling of name pronunciations (with suitably gracious apology). What could be more American than that?

In an especially moving moment, the emcee invited children in the audience who knew the Pledge of Allegiance to come to the front and lead the recitation by the new citizens. The kids, so proud, flocked forward. (I think the words “under God” are clearly unconstitutional, but that was the sort of carping I tried to suppress for the occasion.) Finally, another video: Lee Greenwood singing “God Bless the USA” with heartwarming photos of immigrants and soldiers. I couldn’t help crying at the idea of starting over with nothing in a free land. It isn’t a perfect land, but it is pretty great. My son-in-law went to prison in East Germany for three years, at the age of 18, for putting up one poster criticizing the communist system, so I know he feels that. Hokey, yes; flawed, surely — but also real.

Nineteenth-century Italian nationalist Mazzini said that people have a hard time wrapping their minds around abstract ideals of human rights. A nation, however, with its rich history, its geographical concreteness, its real people, could become the object of strong emotions. Those emotions, if suitably tethered to high ideals, could move people toward the good in a way that the ideals by themselves never would. That both Greenwood and Beyoncé have made “God Bless the USA” their own says much about the truth of Mazzini’s contention.

We hear of a fractured America, of a need for healing. In Denver, I saw, with renewed hope, the America we aspire to be — a welcoming America, with open arms for all who are willing to learn, work and serve. I’m sure if I went to a similar ceremony in Chicago I would see the same thing. Our polarization is bad. There is surely too much fear and mistrust of immigrants. On the ground, though, most of what I see is different: warm acceptance and celebration, willingness to help and foster the naturalization process.

The cynical left has a lot to learn from my day in Denver. So, too, do doubters and fear-mongers on the right. Here’s a multiethnic city, verging on majority-minority (non-Hispanic whites comprise only 52 percent), that pulls together to create one of the nation’s strongest economies. Here we all were, in a non-affluent suburb, with people from 30 different countries taking the citizenship oath, with only welcome and good will. A majority were brown and black, but nobody really noticed. The Europeans were the odd ones out, the Belgians so much taller than others, the Germans and Czechs with the names that our emcee (clearly fluent in Spanish) found most difficult to pronounce. And the half-skeptical academic was the oddest one out of them all.

Even the Homeland Security bureaucrats gave me hope. They were so respectful, so joyous, so happy to let children run around and play, quite the opposite of the rude face we usually imagine and unfortunately sometimes see. I admired the group of new citizens; they had evidently put a lot of work into selecting them. The only thing I could say against them was that their security rules made me leave my Clif Bar outside the building, where I planted it in a snowdrift for safekeeping. But you know what? When we were through, it was still there, deep frozen, sticking up like a cheerful flag.