Iran is a death-penalty machine. More than 600 people were executed there last year, according to the United Nations, many of them in public hangings before crowds filled with children.

So far this year, there have been an estimated 188 executions. That number would have been 189 had it not been for the family of Abdollah Hosseinzadeh, an 18-year-old knifed to death in a street fight seven years ago.

Islamic Shariah law gave the young man's mother, Samereh Alinejad, the right to extract revenge by participating in the execution of the man who killed her son. As the convicted murderer stood in the gallows, a noose around his neck, she was called forward to help kick the chair out from under him and administer the ultimate punishment.

Instead, she shocked the crowd by first slapping his face and then publicly forgiving him. After her husband removed the noose, Alinejad and the killer's mother embraced, both of them sobbing. At least one of their sons had been spared.

Our fundamental choice about capital punishment doesn't get more stark than in this story, which was caught on video and went viral on the Internet and social media.

That's because for all the purported justification of capital punishment - claims of closure and discredited notions of deterrence - executions touch all of us personally. In a metaphoric sense, an execution requires each of us to look the killer in the eye and kick out the chair.

We insulate ourselves from this uncomfortable fact through distance. We assign the deed to others, who strap the convicted person into the electric chair or jab the needle into his or her arm.

We hide the executioner behind a screen, prohibit photos, nod our heads over media accounts as we carry on with our lives. There's a reason we give a blank bullet to the firing squad: That way, each marksman can believe his wasn't the fatal shot.

Yet there will always be something to jar us out of our denial.

Last Monday, it was a statistical study published online by the Proceedings of the National Academy of Sciences. Researchers examined data on exonerations and concluded that 4.1 percent of those sentenced to death in the United States are innocent. The researchers estimated that 340 people have been wrongly sentenced to death in America since 1973.

Last Tuesday, we were again forced to consider capital punishment when a botched lethal injection in Oklahoma led to the agonizing 43-minute death of an inmate who, after being declared unconscious, began moaning and writhing until he succumbed to a heart attack.

Last year, it was the TV series "The Killing" that forced viewers to confront state-ordered executions. In the penultimate episode of the season, actor Peter Sarsgaard's character, a death row inmate, was executed.

When asked how he approached the part, Sarsgaard said his aim was to bring people closer to the reality of capital punishment.

Nothing has brought us there like Alinejad, the grieving mother. And no one can teach us better about the ultimate reason to stop the death-penalty machine.

"I feel I'm at peace," she said later. "I feel that vengeance has left my heart."

That Abdollah's parents chose forgiveness in such a dramatic fashion gives me hope that the closer we get to the person in the noose and the more we take responsibility for the barbarity of state-sanctioned executions, the less likely we'll be to help kick out the chair.

Mike Farrell, who played B.J. Hunnicutt on the television series "MASH," is president of Death Penalty Focus, a nonprofit organization dedicated to the abolition of the death penalty. He wrote this for the Los Angeles Times.

Distributed by MCT Information Services