BILL MOYERS: Welcome to the Journal.

Here at the end of this watershed week, one photograph keeps playing in my mind, and I want to share it with you. It's from an Obama rally in St. Louis, Missouri, a couple of weeks ago—100,000 people.

Now look more closely at the background, at that old building with a copper dome turned green with age. That used to be the courthouse where slaves were auctioned from the steps. In 1846, Dred Scott and his wife Harriett, both slaves, went there to appeal to the court for their freedom. They said they had been living in states and territories where slavery was outlawed and so should be let go.

They were, briefly, but soon were returned to slavery. When their appeal reached the United States Supreme Court, 11 years later, Chief Justice Roger Taney refused to free them. He ruled that slaves did not have the rights of citizens because Harriet and Dred Scott were, quote, "Beings of an inferior order, and altogether unfit to associate with the white race, either in social or political relations, and so far inferior that they had no rights which the white man was bound to respect."

You know the storm that followed—civil war, Lincoln's assassination, the failure of reconstruction, Jim Crow, white supremacy, lynching. So much blood shed, so much suffering, so many martyrs.

My grandchildren have a hard time understanding the America I try to describe to them from my own childhood in East Texas. Across the Deep South whites still resolved to keep blacks in their place, often with a holy fervor.

Above all they were determined to keep blacks from voting, voting meant equality, power. When black veterans coming home from fighting for their country tried to register, they were assaulted and arrested. In South Carolina, one black soldier riding the bus home after 15 months in the South Pacific, angered the driver with some minor act that struck the white man as uppity. At the next stop the veteran was taken off the bus by the local chief of police and beaten so badly he went blind. The police chief was put on trial and acquitted, to the cheers of the courtroom.

In one Georgia county the only black to vote had also just come home from the war. As he sat on his porch the day after the primary, he was shot and killed, and a sign posted on a nearby black church boasted: "The first nigger to vote will never vote again."

Signs like that did not come down easily. It would take Montgomery, Birmingham, Selma. It would take the Civil Rights Act and the Voting Rights Act, and countless individual acts of heroism. And it would take, finally, take someone like Barack Obama, who, if he had been born a generation earlier, could have been lynched for the audacity of hope, but who now saw that America was changing, is changing, has changed, and that he might be the agent for lifting from around our necks this great stone from the past, by refusing himself to be haunted or ruled by it.

He will of course disappoint—all presidents do; and the first black president will be no more exempt from reality and human nature than the 43 white men who came before him. We don't know what he will do in office. He has promised that he will take us "there" without saying what "there" entails, or what hard choices must be made. We shall see.

But that is ahead of us. For now, it is only right that we remember how long it has taken to get here, and the price paid by so many to bring us this far. The reality of it hit me late in the week as I read in the San Francisco Chronicle of a woman named Johnnie Marie Ross. Forty years ago, in 1968, she was 19, and the mother of two, and she was shattered by the assassination of Martin Luther King Jr. To cope with her pain she wrote a poem:

"So rest in peace in the name of the father and the son, for your dream has not ended but in reality just begun."

When she read her poem aloud at a local church service, young black people from the neighborhood passed the collection plate and sent her to Dr. King's funeral in Atlanta. "He was our everything," she told the "Chronicle" reporters. "He was our hope for the future." But after his death, she said, "We were afraid... like we would be killed if we stood up."

That was 40 years ago. Johnnie Marie Ross, now 59, says she has lived in fear ever since. No more. On Tuesday she voted and walked home with a flag in her hand and a song on her lips. Hallelujah, she sang, over and over. Hallelujah.

All the way home.