America may seem leaderless, with nastiness and bullying ascendant, but the best of our nation materialized during a moral crisis on a commuter train in Portland, Ore.

A white man riding on that train on Friday began screaming anti-Muslim insults at a black 16-year-old girl and her 17-year-old Muslim friend wearing a hijab. One can imagine people pretending not to hear and staring fiercely down at their phones; instead, three brave passengers stepped forward to protect the girls.

The three were as different as could be. One was a 23-year-old recent Reed College graduate who had a mane of long hair and was working as a consultant. Another was a 53-year-old Army veteran with the trimmest of haircuts and a record of service in Iraq and Afghanistan. The third was a 21-year-old poet and Portland State University student on his way to a job at a pizzeria. What united the three was decency.

When they intervened, the man harassing the girls pulled a knife and slashed the three men before fleeing. Rick Best, the veteran, died at the scene. Taliesin Namkai-Meche, the recent Reed graduate, was conscious as he waited for an ambulance. A good Samaritan took off her shirt to cover him; she recounted that some of his last words were: “I want everybody on the train to know, I love them.” He died soon after arriving at the hospital.

Another passer-by stanched the bleeding of the student poet, Micah Fletcher, and called his mother to tell her to go to the hospital — but played down the injuries to avoid terrifying her. Fletcher underwent two hours of surgery to remove bone fragments from his throat and is recovering.

Police arrested Jeremy Christian, 35, a white supremacist, and charged him with the murders. The train attack doesn’t fit America’s internal narrative of terrorism, but it’s a reminder that terrorism takes many forms. Last year Americans were less likely to be killed by a Muslim terrorist (odds of one in six million) than for being Muslim (odds of one in one million), according to Charles Kurzman of the University of North Carolina.

In tragedy, we can sometimes find inspiration. In that train car, we saw that courage and leadership are alive — if not always in Washington, then among ordinary Americans converging from varied backgrounds on a commuter train, standing together against a threat to our shared humanity.

I’d been dispirited by recent events. President Trump’s overseas trip marked an abdication of American leadership, with German Chancellor Angela Merkel concluding that Europe can no longer rely on the United States. The Trump budget was intellectually dishonest and morally repugnant, with cuts in global AIDS funding alone that may cost one million lives.

Today’s White House seems to stand for nothing loftier than crony capitalism and the scapegoating of refugees, Muslims and immigrants. To me, Trump “values” are primarily narcissism, nepotism and nihilism.

And this is infectious: Cass Sunstein of Harvard cites psychology research indicating that Trump has made it more acceptable for Americans to embrace xenophobia. I wrote last year that “Donald Trump is making America meaner,” prompting bigotry in rural Oregon where I grew up, and around the country.

We don’t know whether the murderer on the Portland train felt empowered to scream at a Muslim girl because of Trump’s own previous Islamophobic rants, any more than we can be sure that Trump’s denunciation of reporters led a Montana candidate to body slam a journalist. But when a president incites hatred, civilization winces.

If all that is one thread of America, another is represented by those three men who stepped forward on that train. It’s also represented by the good Samaritans who helped them when they were stabbed, by the countless people who joined vigils to honor the victims and who donated more than $1 million in a few days for the families of those killed and for the survivor.

It’s terrific that the White House eventually acknowledged these heroes in a tweet. But it would have been more convincing if the tweet came sooner and from Trump’s own @realDonaldTrump account rather than the @Potus account mostly managed by his staff.

What the three men in Oregon understood, but the White House doesn’t, is that in a healthy society, Islamophobia doesn’t disparage just Muslims, racism doesn’t demean blacks alone, misogyny hurts more than women, xenophobia insults more than immigrants. Rather, we are all diminished, so we all have a stake in confronting bigotry.

Best, the veteran, had three teenage children and a 12-year-old daughter, and I hope his kids understand that their dad died challenging a venomous intolerance that threatens our social fabric. He fell on the battlefield of American values. He deserves the chance to be buried at Arlington National Cemetery.

One thing I’ve learned in my reporting career is that side by side with the worst of humanity, you find the best. The test for all of us is whether we can similarly respond to hatred and nihilism with courage and, in the dying words of Namkai-Meche, with “love.”

After coming out of surgery, weak but indomitable, Fletcher wrote a poem that offers us guidance. According to the Oregonian, it read in part:

“I, am alive.

I spat in the eye of hate and lived.

This is what we must do for one another

We must live for one another.”