As we commemorate the 1963 civil rights march on Washington, it’s worth remembering how close it came to not happening at all. When A. Philip Randolph and Bayard Rustin started shopping the idea, the Urban League declined to support it, the N.A.A.C.P. refused to commit one way or another, and Martin Luther King and the Southern Christian Leadership Conference were too busy with other challenges to get engaged. President John Kennedy argued that the march would hurt the chances of passing legislation.

It was only the events in Birmingham, Ala., in early May — the police beatings, the snapping dogs, the fire hoses turned on people — that galvanized the movement. Without Bull Connor’s brutal overreaction, there might not have been a history-making march.

It’s also worth remembering that while today we take marches and protests for granted, the tactics of the civil rights movement had deep philosophical and religious roots. The leaders rejected the soft meliorism of more secular activists, the idea that significant progress could be made through consciousness-raising and education campaigns, through consensus and gradual reform. As Rustin put it, African-American leaders like him looked upon “the middle-class idea of long-term educational and cultural changes with fear and mistrust.”They wanted a set of tactics that were at once more aggressive and at the same time deeply rooted in biblical teaching. That meant the tactics had to start with love, not hate; nonviolence, not violence; renunciation, not self-indulgence. “Ours would be one of nonresistance,” Randolph told the Senate Armed Services Committee all the way back in 1948. “We would be willing to absorb the violence, absorb the terrorism, to face the music and to take whatever comes.”At the same time this tactic was not passive. It was not just turning the other cheek, loving your enemies or trying to win people over with friendship. Nonviolent coercion was an ironic form of aggression. Nonviolence furnished the movement with a series of tactics that allowed it to remain on permanent offense.

It allowed leaders to stage relentless protests, sit-ins and marches that would force their opponents to do things against their own will. Nonviolence allowed the leaders to expose the villainy of their foes aggressively, to make their enemies’ sins work against them as they were exposed in ever more vicious forms.

The stereotype of the day held that a large gathering of determined black marchers would inevitably turn violent and unruly. But the whole point of this philosophy is that you defeat your opponents with superior self-discipline. These days, protesters from the Tea Party to Occupy Wall Street like to be fully demonstrative, expressing their rage or whatever. But the early-1960s civil rights tactics demanded relentless self-control, the ability to step into fear without ever striking out, to remain calm and deliberate in extreme circumstances, to exercise emotional discipline.

As befitting what was largely a religious movement, the idea was not only to change society but to work an inner transformation. They clung to this in a way that is humbling for the rest of us, who stumble and fall in far easier circumstances.

The idea was to reduce ugliness in the world by reducing ugliness in yourself. King argued that “unearned suffering is redemptive.” It would uplift people involved in this kind of action. It would impose self-restraint. At their best, the leaders understood that even people in the middle of just causes can be corrupted. They can become self-righteous, knowing their cause is right. They can become smug as they move forward, cruel as they organize into groups, simplistic as they rely on propaganda to mobilize the masses. Their hearts can harden as their enemies become more vicious. The strategy of renunciation and the absorbing of suffering was meant to guard against all that.

In short, the method relied upon a very sophisticated set of paradoxes. It relied on leaders who had done a lot of deep theological and theoretical work before they took up the cause of public action. Nonviolent protest, King summarized, “rests upon two pillars. One, resistance, continuous military resistance. Second, it projects good will against ill will. In this way nonviolent resistance is a force against apathy in our own ranks.”And yet it worked. And sometimes still does. It’s commonly said that nonviolent protests work only in a context in which your enemies and the watching nation have a conscience to be appealed to. But that is often enough, apparently. A study by Maria Stephan and Erica Chenoweth in the journal International Security found that between 1900 and 2006, movements that used nonviolent means succeeded 53 percent of the time, while violent resistance campaigns succeeded only 26 percent of the time.

So that’s what we are commemorating: The “I Have a Dream” speech, of course, but also an exercise in applied theology.