One day last week, as the Cambridge clamor over a “teachable moment” escalated all the way to the White House, Dan Conley, the Suffolk District Attorney, quietly drove himself to a middle school auditorium on the Dorchester/Mattapan line.

Before an audience of a hundred inner city kids, many of whom were no strangers to random violence and malignant dysfunction, Conley spent the better part of two hours involved in a teachable moment that may well have far more profound consequences than tomorrow night’s overexposed fandango in Washington.

The message Conley delivered to the day campers of the Red Auerbach Future All Stars Program was simple:

The choice made in a single moment can either end your life, or change it forever. These boys and girls, all of whom were black, listened intently to the middle-aged white gentleman who’d grown up in Hyde Park and recalled a couple of the choices that saved his own.

“Two of the boys I grew up with are dead from drug overdoses,” Conley told the campers. “Another is in prison.”

If not for an Irish father who forbade him from falling in with a doomed crowd, and the Italian mother who kept him and his siblings on a very tight leash, “I wouldn’t be standing here talking to you now.”

But the lesson Dan Conley carried with him into the Lee School last week was the story of Daquadry Norman, an aspiring 15-year-old gangbanger who almost killed a beloved Pop Warner coach named Myron Stovell over a confrontation about Norman’s unleashed pit bull.

Conley held up The Herald’s account of Daquadry Norman’s guilty plea last week for shooting Myron Stovell, back in October of 2007, after the coach’s car grazed Norman’s dog.

“Myron Stovell’s apology wasn’t good enough for Daquadry Norman,” Conley said. “No, he came back with a gun and to impress his boys and he shot at Mr. Stovell three times. Mr. Stovell was hit once in the leg and could have died. And it was just a miracle no other children were hit by those other bullets.”

Conley told the kids that a 15-year-old’s bad choice put him in a grown-up prison for at least the next three years. “Hard time, boys and girls. Hard time for a bad choice,” he said.

Just before Conley went back downtown, a boy with soft eyes and a hushed voice whispered a final question: “My dad’s in jail for three years, what do I do?”

“There’s people who love you,” the prosecutor said. “Stay close to them. Listen to them.”