Once, when I was a child, old enough to detect but yet to understand the contrariness of life, I observed a strange behavior by my grandmother.

An in-law had appeared on the perimeter of our yard, and clearly upset about something, she first resorted to hurling angry words and then stones at my grandmother. My grandmother, who was sitting and shelling peas for dinner just outside the doorway of our lean-to log kitchen, ushered me out of harm’s way but she remained in place and continued to shell her peas.

I remember watching in wonder as the stones ricocheted off the loose kitchen logs around her, and being dismayed that she wasn’t responding to this clear intimidation by the in-law.

In looking back years later, I have often wondered whether the in-law really meant to harm my grandmother. None of the stones hit her, and the in-law, perhaps sensing her intimidation tactic was not working, eventually walked away.

I would come to know, however, that my grandmother’s nonviolent response was part of her nature. I also came to understand that her stance that day exhibited the greatest of courage, to stand one’s ground without responding in kind to the violence directed at you.

And while I would like to think I have her courage, I can't say for sure. I have not been really tested. I have spent most of my life behind a byline, mostly looking out over the fray of life. Yet, I have seen this courage in many others over the years.

And I was reminded last week of the cost of this courage by Heather Heyer of Charlottesville, Virginia, when she went to peacefully protest the hate and bigotry of Nazis and white supremacists, many of them carrying weapons. One of them killed her and injured 19 others with his car.

At her funeral, her mother, Susan Bro, honored Heather by picking up her defiant social justice mantle while preaching nonviolence.

"Let's channel ... anger not into hate, not into violence, not into fear, but let's channel that difference, that anger, into righteous action,” she said.

"Say to yourself, 'What can I do to make a difference?' That's how you're going to make my child's death worthwhile."

Ms. Bro’s response echoes those of the late South Carolina state senator and pastor Clementa Pinckney, who used to speak of the necessity of presenting “righteous indignation” in the face of injustice.

Pastor Pinckney, as you may recall, was among the 17 parishioners murdered by a white supremacist while they were attending services inside Emanuel African Methodist Episcopal Church in Charleston on June 17 two years ago.

We are, however, living in period of injustice and resurgent bigotry, and there are groups on the left, such as antifa (a contraction of anti-fascist), that are questioning whether these scourges should be confronted more forcefully.

“People are starting to understand that neo-Nazis don’t care if you’re quiet, you’re peaceful,” one such adherent, Emily Rose, said in a New York Times article last week.

“You need violence in order to protect nonviolence. That’s what’s very obviously necessary right now. It’s full-on war, basically.”

But others, such as peace activist Scott Schaeffer-Duffy, disagree.

He points to a 2008 International Security journal article by Maria J. Stephan, director of educational initiatives at the International Center on Nonviolent Conflict, and Erica Chenoweth, assistant professor of government at Wesleyan University, in which they argue that nonviolent civil disobedience is far superior to violent confrontation.

They arrived at this conclusion after studying “nonviolent and violent resistance campaigns from 1900 to 2006,” and finding that major nonviolent campaigns achieved success 53 percent of the time, compared with 26 percent for violent resistance campaigns, they said.

The researchers gave two reasons for this success rate: While governments can easily justify violent counterattacks against armed insurgents, acting violently against nonviolent movements is more likely to backfire. In addition, nonviolent resistance encourages more broad-based support for group grievances.

Mr. Schaeffer-Duffy said individuals such as Ms. Rose appear to be making a choice between violence and cowardice, and thus choosing compulsion over persuasion.

“They may succeed in the moment, but they are not changing hearts and minds,” he said.

“They are promoting their cause by allowing the other side to see themselves as victims.”

Yet, we are living in a world in which mutual assured destruction is our security blanket and in which many of the same people demanding nonviolent social justice protests at home are the same ones supporting pre-emptive military strikes abroad. It is clear that many people pay lip service to nonviolence to protect their own interests and not to advance social justice causes.

So, you go ahead. Call for nonviolence all you want, but if you are not out there like Heather Heyer was, peacefully taking righteous actions and showing righteous indignation, you don’t have the courage of your convictions.