Spencer Stone, Alek Skarlatos, and Anthony Sadler had more than the great reflexes, courage, pure luck — and, in Skarlatos and Stones’ cases, the military and medical training — necessary to subdue an armed terrorist and to aid a victim on a high-speed train from Amsterdam to Paris.

The three young Americans also had the remarkably high, democratic morale that some would consider peculiarly American because it had been nourished by their long, casually interracial camaraderie since middle-school days. Its vigor and generosity reminds me a little of the “Why We Fight” essay that won my father a two-day pass from the 277 th Battalion Army Corps of Engineers in France in 1944. Unfortunately, though, it also reminds me of something that’s peculiarly American in less-encouraging ways.

“We fight,” my Dad wrote, “because hatred of others’ race or creed makes us mad as hell.” The Army was segregated then, however, and few of my father’s fellow G.I.’s were mad as hell about racism. Still, as a son of Lithuanian-Jewish immigrants, moving across France, Belgium, and Germany in an American uniform, he had good reason to write what he did, and he’d have been thrilled now to see not only the alacrity and altruism of these young Americans but also the irrelevance of Sadler’s blackness to their performance.

For that we can thank whatever halting efforts toward racial integration facilitated Sadler’s bonding with Stone and Skarlatos more than a decade ago in their California middle school. And we can thank the military for becoming one of the more constructively integrated institutions in America.

As in 1944, though, there’s another side to this story. Although the situation confronting the three Americans on the French train was as unambiguous morally as the war against Hitler on that same turf, its causes this time are, if anything, murkier.

This time, the assailant was “radicalized” after Americans had spent billions dollars on funding radical Afghani Islamicists — some of whose followers Skarlatos has been fighting in that country — and hundreds of billions of dollars more on deranging a brutal but stable Iraq, empowering Islamicists who made it far more dangerous to what our three American heroes represent than it was before American leaders stampeded the American people into that country.

At home, meanwhile, websites and gun-running tactics as destructive as those that radicalized the assailant last week in France have “radicalized” white supremacists and reactive black nihilists. An all-too American racist like Dylann Roof, who massacred nine African-Americans in a bible class in Charleston, might as easily have taken aim at an Anthony Sadler simply for hanging out with two white guys. An aggrieved black man like Colin Ferguson, who in 1993 boarded a Long Island Rail Road train with a Ruger P-89 9 mm handgun and 160 rounds of ammunition and massacred six and wounded 19 white passengers, might have taken aim at Stone and Skarlatos.

That such shooters and their counterparts are deranged hasn’t made them less acute in picking up and acting upon signals and undercurrents that are far more widely shared and aggressively distributed than we like to think. Our real assailants are the people and commercial engines who are sending those signals, whether mindlessly for profit or malevolently for vindication of some kind. More than the terrorists, they’re generating undertows in our political culture that Stone, Skarlatos, and Sadler have avoided but that others are resisting less effectively.

My father seldom talked about his experiences in World War II. He believed that he’d operated there under Hobbesian conditions of lawlessness, force, and fraud only in order to save others back home as well as in Europe from having to think of civilian life as Hobbesian, tribal, or warlike in the future. Like Stone, Skarlatos, and Sadler, who were traveling interracially and unarmed, he didn’t want to see civilian life overtaken by calculations based on force and fraud that eclipse the kind of freedom that comes only with mutual trust. He didn’t want civil society to morph gradually into that of “The Sopranos,” “House of Cards” or “Jarhead.”

Alexander Hamilton wrote that history had destined Americans, “by their conduct and example, to decide the important question, whether societies of men are really capable or not of establishing good government from reflection and choice, or whether they are forever destined for their political constitutions on accident and force.” Hamilton wasn’t sure which it would be.

What Stone, Skarlatos, and Sadler did almost instinctively in France offers the first glimmer of hope I’ve seen in some time for a public life guided by reflection and the freedoms of choice that come with trust and dialogue. But too much of what else is happening in America these days makes me wonder what these young heroes can do to thwart arrangements and undertows far more ambiguous than the challenge they confronted on that train.

Jim Sleeper

Jim Sleeper is a lecturer in political science at Yale. He is the author of The Closest of Strangers: Liberalism and the Politics of Race in New York and Liberal Racism.