For those who doubt the existence of white privilege, I'd like to tell a story.

A number of years ago, my wife (who is black) and my two biracial children and I lived in a well-off neighborhood near Lake Harriet. It was a beautiful Saturday afternoon in late May, and we had company up from Des Moines for the weekend. The women were out somewhere, and my friend Jim was in the living room falling asleep over a book. I was watching the Twins on TV.

My then-13-year-old son Frank, who had been upstairs, came into the TV room and asked me if he could go down the block to visit his friend Matty. I told him that was fine, but asked him to check in with me if nobody was home. He left, but was back five minutes later, saying that nobody was home down there and asking if he could ride his bike down to the lake. I OK'd this, told him to be home by 5, and he hopped on his bike and rode away, out of the story.

Thank God.

I went back to my ballgame, but the day was so fine that I decided to go for a walk myself. Jim was sound asleep on the couch by now, so I left him a note and headed down the driveway to the street. At the foot of the driveway, a scrawny-looking white guy was standing, staring up the sidewalk. I looked to see what he was staring at, and saw that three or four houses down, in front of Matty's house, a gaggle of squad cars was parked and five or six cops were getting out of them. One had a police dog on a leash.

I walked up to the scrawny white guy and said, "Excuse me, but do you know what's going on down there?" "Yeah," he said excitedly, "I think there was a burglary!" "What makes you think that?" I asked. He replied, "Well, I was driving by here about 15 minutes ago, and I saw this black kid up in the yard, and I knew he had no business there, so I called 911!"

Part of me wishes that I'd knocked this guy right on his ass there and then. But I didn't. Instead I made a beeline for the cops. By the time I got there, all of the cops but one had made their way to the back of the house. The remaining cop was standing at the front corner, looking intently down the side yard, his gun drawn.

I walked up the yard and said to the cop, "Excuse me, officer, but I think I can explain what happened here." He looked at me as though he thought I was crazy and hissed, "Get away from here! There's a burglary going on!" I didn't go away. Instead, I told him about my son, and Matty, and how Frank was now probably down at the lake.

As I was finishing my story, the rest of the cops, and the dog, were making their way back to the front of the house, having found nothing and looking a little deflated. My cop, who had listened to what I had told him, went over to the others, and they all had an animated conversation. Two of the cops then peeled off up the street, where they confronted the scrawny white guy and chewed him out. Then they all got in their cars and drove away, leaving me on the sidewalk to contemplate how fortunate we had been.

You see, Matty's mom frequently left her back door unlocked, and it had been unlocked on this beautiful late spring day. And Matty had a television set and a game console in his upstairs bedroom. And Frank had carte blanche to play on it. And at the time, Frank was being treated for attention deficit disorder.

What God it was that kept Frank from going through the unlocked door and up to Matty's room, where the cops undoubtedly would have found him, I have no idea. As a retired public defender, the best result I could have expected would have been an arrest, a weekend at the juvenile detention center, and a lot of explaining to various juvenile law enforcement and court personnel. At worst, a "furtive movement" on Frank's part, induced by fear and heightened by his ADD, leading to an attack by the dog. Or a bullet.

Who did something wrong here? Certainly not the cops. They responded speedily, took all due precautions and even set the scrawny white guy straight. You could even say that in our security-conscious age, the scrawny white guy was only being hypervigilant.

Who did something wrong? Frank. He walked up to a front door in an affluent neighborhood. While black.

If you're white and have a 13-year-old son, do you imagine he could end up facing five armed cops and a police dog because you told him it was OK to go down the block and knock on his friend's door on a sunny Saturday afternoon in May? Do you wonder, as I did that day, how to turn an incident like this into a teaching moment for your son, without telling him he's not free to walk down the street in his own neighborhood to see a friend unless he takes some sort of, um, precautions? And what kind of precautions should he take? Change the color of his skin?

If you have never had to ask yourself questions like this, I'd suggest it's because you have white privilege. It's probably not something that you sought, and I'm glad you have it. But my kids don't, and I don't, and we never will unless, for starters, you stop doubting it exists.

Richard G. Carlson, of Minneapolis, is a retired assistant public defender.