Last night, someone tore out a piece of America. Five hard-working, brave policemen of the City of Dallas are dead. Seven others lie wounded, as do two civilians. Racial resentments, not wholly groundless, have been needlessly inflamed. All this in Dallas, a vibrant, economically thriving city where before the shooting, cops were posing for photos with the Black Lives Matter protestors whom they were there protecting; where misconduct by members of our highly diverse police force has plummeted thanks to higher quality training; where the black citizen carrying the AR-15 whom someone misidentified as a suspect was in fact a law-abiding gun owner exercising his Second Amendment rights, who handed his rifle to the cops in case they needed it.

As Dallas Police Chief David Brown said at the prayer rally I just left in downtown Dallas’ Thanksgiving Square, “We will not let that person steal this democracy from us.” The mood here isn’t sour. At that rally, evangelical preachers black and white, a rabbi, an imam, and the city’s Catholic bishop led a multiracial crowd of more than 1,000 in prayers for the police and for racial healing. We held hands and prayed, and the Salvation Army band sweltered for our benefit, playing “God Bless America.”

Nationally, things are bleaker. Social media bubble with charges and counter-charges. Each of the major presidential candidates is so divisive that it’s a blessing neither of them chose to visit. It’s also very sad: presidential election opponents Jimmy Carter and Ronald Reagan, even George W. Bush and Al Gore, could have (and probably would have) changed their plans and made an appearance in Dallas, after the worst strike against law enforcement in more than 100 years. This year, neither of the candidates has any place preaching healing or unity.

We citizens will have to. We must work together closely, and control our “gut” reactions — which while they sometimes partake of common sense, are also deeply entwined with our fallen reason and passions. It is “natural” to be tribalist and side with those who look like us, in the same sense and for the same reasons it is “natural” to lie, to cheat and to steal. That “natural” man is doomed to die.

Downtown Dallas is a ghost town, with traffic blocked off from my neighborhood, which as of this morning was still a vast crime scene. Oh yes, I live down here. The shooting started in a park where I’d walked my dog the night before, and had almost decided to take her again last night. Instead, I was on my way to a restaurant when I saw a vast wave of police vans hurtling down the street. I rolled my eyes, and asked someone: “Is Obama in town? Or are the police on strike?” That drew a nervous chuckle. It’s illegal for policemen to go on strike, for excellent reasons I don’t need to explain.

As I sat peacefully eating Mexican food served me by third-generation Latinos, near a tired-looking black guy who’d just come from work, we learned what was actually happening. Together, we watched the scene unfold on TV — as 15 years ago, I stood with a crowd in a New York City Starbucks and watched 9/11 happen.

The real split, as Aleksandr Solzhenitsyn knew, runs not between parties, races or religions. It’s the line that divides the human heart itself …

How bizarre it is to see a violent rampage on a monitor and recognize all the street signs, landmarks, storefronts … because all of it is still happening just two blocks down the street. When I finally walked the dog, my super warned me to make it brief: “There’s a least one active shooter still at large.” Uh, yeah, we made it brief.

After dashing back in, I settled down to follow events on Twitter, and “learned” that there might be bombs planted all around my neighborhood. That this might be the work of al Qaeda, which recently called on its operatives to play on racial divisions. That there were multiple shooters, who’d crouched in auto parking garages and shot with military precision. Most of this turned out not to be true, but it sounded all too plausible with the noise of all those police choppers buzzing over my building.

Last night brought me back to New York City in the 1970s. If you’ve never seen it, Spike Lee’s Summer of Sam is a powerful document of memory. It immerses you in the moment when a rampant serial killer (Son of Sam), a record heat wave, an electrical blackout and massive street looting brought our nation’s greatest city to the brink of civic collapse. The film depicts the powerful role that racial division plays in making order harder to keep and justice tougher to find.

But ultimately, it isn’t the conflict between one group and another that causes chaos. In a lily-white society like 1930s Germany, or an all-black republic like 1990s Rwanda, we will still find sufficient divisions to make us hate each other, if that’s where our hearts incline. And incline there they will, if we don’t push back continually against the powerful currents that otherwise sweep us along — the world, the flesh and the devil.

The real split, as Aleksandr Solzhenitsyn knew, runs not between parties, races or religions. It’s the line that divides the human heart itself, between what we’re inclined to do because it is easy and obvious, and what our conscience tells us instead.

Every last little piece of the social chaos that feeds the crime that draws the cops, who fear for their lives and sometimes panic with tragic results, was born on the wrong side of that line. For instance, when a father walks away from his responsibilities, leaving a single mom to raise her kids as wards of the state. Those boys whose best glimpses of manhood are “thugs” and dealers, grow up without the example of how to control and hone their anger, how to sacrifice themselves slowly, piece by piece, in the way that good men do, on the altar of their families.

Instead the State supports a mangled fragment of a family, processes the children through the assembly line of soulless and godless public schools — some of them as grim and mediocre as the worst East German shoe factory. And the cops, when they’re called, are expected to fill in the yawning chasm where order never grew. No wonder, but no excuse, that a few of them give in to scorn, callousness and a too-hurried recourse to violence. That line runs through their hearts, too.

And it runs through each of ours. For some of us, the price of crossing it is more obvious in this world than it is for others. The illegitimacy rate among working class white Americans is right now where it stood among black Americans in 1965, when Daniel Patrick Moynihan warned that the breakdown of the black family posed a national crisis. Prescription drugs and meth are doing now for my people — dad was a mailman, son of Croatian immigrants; mom grew up malnourished with alcoholic parents and dropped out of high school — what heroin and crack accomplished among blacks in the last generation: leaving millions of lives in ruins.

The self-congratulatory hedonism that erupted in the late ’60s was something that the upper-middle class could sometimes handle. If your dad’s insurance will cover rehab, if he can afford to back you while you “burn out” then “find yourself,” maybe you can emerge mostly intact from a few years of recklessness. All those millions of quiet abortions that men like Hugh Hefner made both necessary and legal have left their scars, of course. But we can pretend not to see them.

And if we have been more careful, or simply a little bit luckier, we can think that the islands of order we inhabit are free of sin — that vice and self-destruction is something that happens to “those people,” whom we trust the cops to keep far away from us, or under lock and key.

It only takes one flash of evil, at the hands of a single gunman, to rip away that illusion. That’s a revelation each one of us is guaranteed on the day when we breathe our last. We cannot stay on the right side of Solzhenitsyn’s line. Not by ourselves. What unites us is our helplessness, our absolute need for Grace, which only comes in one color — the deep, rich red that flowed from the Cross.