January 19

MARTIN LUTHER King Jr. preached nonviolence, practiced it and led a great movement guided by its principles. Yet surely he knew, as did most of his followers, that what they were doing would lead to violence. One need only look at the old black-and-white photos of civil rights protests, at the hatred, scorn and, perhaps most important, fear on the faces of some of the white people there to confront the demonstrators to understand how such simple acts as sitting down in a bus or entering a restaurant, seeking the right to vote or go to a better school, could lead to the worst sorts of violence — a bitter truth that followed King to the day of his death.

Yet out of that violence came new understanding of a sort: People who had been all but invisible to much of the United States came to be seen through the newspapers and television as individual human beings: women and children being firehosed; war veterans returning home to be subjected to all the humiliations and restrictions of the time (or to be murdered, like Medgar Evers); polite young men trying to get a sandwich at a lunch counter; a dignified woman who refused to give up her seat on a bus; the children killed by a bomb in a Birmingham church. For many Americans, this marked the first time they had come face to face, or had allowed themselves to come face to face, with the cruelty of racial separation and oppression, a century after the official end of slavery.

It was not a new phenomenon. Many of the men who fought to preserve the Union — probably most of them — had little interest in freeing the slaves. Yet as they moved south, saw the faces and witnessed the conditions under which many enslaved people lived, they gained a new sympathy and understanding of how awful it was. Historian Allen Guelzo writes that Union naval officers “who had some chance ashore to see the remains of the slave system for themselves experienced great awakenings.” Adm. Samuel F. Du Pont, who acknowledged that he had once been “a sturdy conservative” on the question of slavery, “was horrified by the conditions he found on the coastal plantations,” writes Mr. Guelzo. Having seen the institution of slavery in person, Du Pont wrote to a friend, “may God forgive me for the words I have uttered in its defense as intertwined in our Constitution.”

The Rev. Martin Luther King Jr. was seen by some as a radical and a troublemaker. The truth is that he had considerable faith in America. He believed that when people saw the unfairness of the caste system that had grown up in their country — in a nation founded on the principles of equality before the law, the opportunity to advance in life according to one’s merits, the right to choose the people who govern us — they would understand how truly un-American it was and it would all come to an end, and much of it has.