Unendurable agony: That is what the families and friends and fellow congregants of nine black worshippers slain in Charleston, South Carolina, are reaping Thursday. It's grown from the violence a white 21-year-old, Dylann Roof, allegedly sowed Wednesday night.

And a version of that agony is spreading across the nation. Is there nowhere, not even a church sanctuary, that can provide sanctuary? Is there no end to the senseless slaughter? Is this truly who we are, a nation so torn by racial strife that it must come, again and again, to violent death?

I grew up in South Carolina, have spent most of my life there. I've spent a fair amount of time in AME (African Methodist Episcopalian) churches, and felt there joyous welcome when any stranger, of any color, came among them to share worship and fellowship.

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So I'm confident that when the shooter showed up at the Emanuel AME Church Wednesday night during a Bible study meeting, those members on hand and the pastor, Clementa Pinckney, would have joyously   allowed him in, excited that a stranger had come among them to bask in the word of the Lord.

Roof reportedly sat with them for about an hour before opening fire, killing nine, including Pinckney.

Pinckney, 41, was a state senator. More important, he was a husband and father of two. He was widely known as a fighter for justice, and an-always composed and loving man of God. Now, he will also be known for the savagery and pointlessness of his end.

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Roof was arrested at a traffic stop in Shelby, North Carolina, Thursday. What's known about him now is that he's been arrested a couple of times, once for drugs and once for trespassing. His uncle, Carson Cowles, told Reuters that Roof was given a .45-caliber handgun as a birthday present in April. The picture being circulated by the media is the one from his Facebook page, and shows a skinny kid in a jacket with flags that reportedly represent Rhodesia and apartheid-era South Africa. He is from Lexington, South Carolina.

The church where this violence exploded is legendary, and traces its roots back almost two centuries. It has been a linchpin and crossroads for the civil-rights movement. One of its founding members led a failed slave rebellion 193 years ago this week.

Is that why this happened? Roof, who according to one of the three survivors of the shooting, told them " 'I have to do it. You're raping our women and taking over the country. You have to go.' "

Two things happened fast in Charleston Wednesday night. The police responded and the onlookers and neighbors and crowds that quickly gathered formed prayer circles.

And across the nation, black people and white people tried to process what had happened.

Again. It echoes the bombing of a Birmingham church and killing of innocent children decades ago. But it also echoes the gun-toting madmen who bloodied Newtown, Connecticut, and Aurora, Colorado, and Fort Hood, Texas. Is the crucial issue violent madness or the racial strife that has been at the heart of this nation, and that we often try to convince ourselves has faded away?

President Barack Obama, who knew Pinckney personally, said, rightly, that he has been forced to speak after such events too often during his presidency. He radiated a quiet, almost impotent fury: about the seemingly unstoppable mass shootings and, perhaps, the endlessly confounding morass of race relations in the United States.

We'll learn more about Roof, his past and politics. But what we know now is that we are a nation repeatedly torn asunder by violence, particularly of late. Race is often at the heart of that violence, as is madness.

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How do we stop this? How do we move past it? How do we heal?

And prevent the next brutal blow?