Robert Leroy Wright, 37, was walking his dog Sunday morning in Southeast Washington when police say he was confronted by a knife-wielding neighbor about “allowing the dog near his yard.” A dispute ensued, and the neighbor, Ellsworth Colbert, 56, stabbed Wright to death, according to D.C. police.

Whether or not this story proves to be as insane as it sounds, the incident as reported does provide a textbook case for legalizing handguns in the District, as well as buttress a ruling Monday by a federal judge that declared significant parts of Maryland’s gun-control law unconstitutional.

To get a permit to carry a gun in Maryland, residents must prove that they have “good and substantial reason” to do so. Hogwash, says the judge. He might have noted that someone like Wright would never have been able to prove that he needed a gun to walk his dog — until Sunday, that is. By then, of course, it would have been too late.

To better understand the benefits of a “concealed carry” firearm, consider how the encounter between Wright and Colbert might have unfolded if Wright had been armed and followed a basic self-defense protocol:

According to police reports, Colbert comes out of his house with a knife in one hand and a stick in the other. Being alert to the approaching threat, an armed Wright would now have several options. He could pull his gun, say, a .40-caliber Glock semiautomatic, which speaks volumes without firing a shot: “Never bring a knife to a gunfight, pal.”

Or he could just wait until the assailant gets close enough to meet the legal definition of justifiable homicide.

In January, two men were pumping gas at a Sunoco station in Prince George’s County when a would-be robber approached with a knife and a can of Mace. Well, wouldn’t you know that the two men turned out to be off-duty D.C. police officers. And out came the Glocks.

Never bring a knife to a gunfight, pal.

On the other hand, never underestimate the knife.

In some places, such as the District, the knife now surpasses the gun as the weapon most commonly used in reported assaults. In the past six months, from September to Feb. 26, there were 397 reported assaults with knives, compared with 278 with guns. This year, there have been more than 110 reported knife assaults and 73 with guns.

There’s a service station at the corner of Martin Luther King Jr. Boulevard and Sheriff Road, at the District and Prince George’s line, that sells assault knives for about $10. The most popular is a spring-loaded Army-style tactical knife with a nasty, three-inch serrated blade curved like a raptor’s claw.

In a kind of “West Side Story”-style gang fight, a large group of youngsters from two rival neighborhoods met up last month for a showdown in Southwest Washington. When D.C. police arrived on the scene, the brawlers ran off — leaving behind a girl bleeding on the sidewalk.

The fight had apparently been arranged on Facebook, according to police. And the knives used were comparably high-tech. But the business end is still just a blade — as convenient in a kitchen as it is deadly in the streets.

Even nice, quiet streets in middle-class neighborhoods like Penn Branch.

Why Wright allowed Colbert to walk right up to him, allegedly with a knife, we may never know. Rule No. 1: If you see someone coming at you with a knife, run the other way. Forget macho. Scream, too.

Wright broke off the encounter and headed home with his dog. But Colbert followed, police said.

Now, if an armed Wright had not already shot Colbert, that would have been the time to do it. A man with a knife following you home? To your wife and children?

Instead, Colbert caught up to him, police said, and a “verbal altercation” ensued — then turned violent. The knife slashed at Wright, cutting his arm then opening up what witnesses described as a “large bleeding gash” on his neck. Apparently in shock, Wright went home and returned to confront Colbert with a shovel.

“You going to stab me?” Wright asked, according to police.

He was stabbed multiple times and died an hour later.

Say what you will about the perils of gun ownership, but nobody can doubt that Wright would be alive today if he’d had one.

To read Courtland Milloy’s previous columns, go to washingtonpost.com/

milloy.