As the argument over guns rages in this election season, two recent killings in metro Atlanta represent the polar ends of the debate — the yin and the yang of self-defense.

First, let's go to south Gwinnett County, where a security video of a diminutive lady with a pistol went worldwide as she emptied a clip on three armed home-invaders, sending one to the hereafter.

The other is the peculiar case of Tex McIver, the politically connected lawyer who apparently shot his wife by accident after fearing he might get caught up in some Atlanta street crime.

The former case was what you'd call a good shooting. An armed man with bad intentions was stopped from ever again victimizing anyone. The video of the shooting could be used as Exhibit A for why someone would have a gun.

The latter case, if we take the McIver camp at its word for what happened, is a remarkably tragic — and stupid — accident.

McIver was riding in the back seat of an SUV, coming home late one evening, when the driver turned off the Downtown Connector because of traffic. The McIvers — his wife, Diane, was in the front and a friend was driving — then got turned around, ending up near the homeless shelter at Peachtree and Pine streets, where the couple’s spokesman said Tex was frightened by some people who approached the car.

Mind you, crime is at historic lows, but that doesn’t register with most people who are bombarded on TV and the Internet with The Horror of the Day.

The couple was alarmed by recent Black Lives Matter protests, their spokesman said in one of the most thick-headed PR suppositions in recent memory. (Remember, Fulton County grand jurors might not be as worried about BLM as McIver). The SUV occupants apparently feared a carjacking was about to go down. So, McIver had his wife retrieve his snub-nosed .38 from the center console in case someone on the street messed with him. No one did.

Within a mile or so, McIver was apparently dozing off after this frightening encounter when the gun, still wrapped in a plastic Publix bag, suddenly went off when the SUV hit a bump, firing through a seat and fatally wounding Diane McIver in the back.

She died later at Emory University Hospital. Police are investigating and are being remarkably tight-lipped.

The narrative above comes from them, the McIver camp, and is the best-case scenario for them, albeit one that could lead to a felony charge such as involuntary manslaughter, Gwinnett County District Attorney Danny Porter told me.

“It’s possible, depending on if the gun was handled or if used recklessly,” Porter said. “You’re aware of a potential danger and disregard that standard.”

I asked the longtime prosecutor about guns and the yin or yang of self-defense.

“That’s the sort of eternal argument; if they’re used improperly, they have tragic results,” he said. “If used properly, they serve the purpose for which they were designed.”

According to the FBI, there were 258 justifiable fatal shootings of felons by private citizens in 2012. By comparison, there were 505 unintentional fatal shootings in the U.S. in 2013, according to the Centers for Disease Control and Prevention.

Jerry Henry, the executive director of GeorgiaCarry, was more blunt about the McIver shooting.

“It’s not an accident, it’s negligence; I can’t see how you can look at it any other way, in my firm opinion,” he said. “It’s a negligent discharge and he’s responsible for her death.”

On the home invasion front, Henry was pleased by the outcome: “That’s what should happen every time someone kicks in a door; if it did, people would get the message.

“She was apparently trained to use the gun, so she got one of them and got the other two out of her house.”

Au contraire, said Porter.

The woman recently got the gun from her husband, Porter said, “but had never fired it.”

Still, he added, “She did what a lot of people can’t do: She fired accurately under pressure. Gun instructors call it spraying and praying.”

Folks worry about home invasions, although doors kicked in by robbing crews are rare. Often the victims are drug dealers or small, legitimate merchants who deal in cash. The woman, whose family ran an Asian restaurant, was the latter. Homegrown robbing crews have invaded the abodes of perhaps 20 Asian restaurant owners in the past three years, Porter said.

The Gwinnett woman’s security video captures three armed men forcing their way in and snooping around a home filled with restaurant supplies. Suddenly, the three flee terrified as the woman charges down the hall firing, then aiming into the front yard, while the intruders shoot back. The robber wearing a long wig ended up dead in the yard. The other two dashed off into the night and are still at large.