Clark exploded. He punched Vivian in the face, sending him sprawling down the steps. A bloodied Vivian got up and confronted Clark again, haranguing him until he was arrested. The image of Vivian's confrontation with Clark was beamed around the nation, and drew more sympathy for the voting rights movement.
"He couldn't deal with the truth," Vivian says of Clark today. "And like the general society, he tried to beat me. He did knock me down and I got up, still talking to him."
Those televised images of brutality were crucial to the success of the voting rights movement. Civil rights activists and lawyers had made moral appeals to Americans for years, but much of the country remained indifferent.
But they could not ignore a preacher getting clubbed by a sheriff. Nor could they ignore the brutality of "Bloody Sunday." The footage of the march in Selma is seared in many people's memories. A group of voting rights marchers led by John Lewis, then a Southern Nonviolent Coordinating Committee activist, and the Rev. Hosea Williams, an aide to King, faced a phalanx of Alabama state troopers at the Edmund Pettus Bridge. The troopers charged the protesters with billy clubs and horses. Lewis' skull was fractured, and 57 demonstrators were hospitalized.
That night, ABC interrupted a showing of the Holocaust film "Judgment at Nuremberg" to show footage of the troopers' attack. An estimated 48 million Americans watched. The nation was no longer indifferent. Thousands of clergy and volunteers answered an appeal by King and descended on Selma for another peaceful march two days later.
The nation's outrage over voting rights was stoked even more after the murder of two white demonstrators who had traveled to Selma after seeing Bloody Sunday footage. Their deaths (a black demonstrator killed during the same time was ignored by the national press) gave President Lyndon Johnson enough political muscle to go on television to address a session of Congress.
Johnson called for the passage of a Voting Rights Act that would protect the rights of racial minorities. The bill would no longer allow states like Alabama free rein to set voting requirements for its residents.
The president ended his rousing speech by quoting the movement's anthem, declaring in his Texas drawl, "And we shall overcome."
Vivian was with King the night Johnson gave his speech. They were watching it on television with a small group of aides at a friend's home. When Johnson quoted, "We Shall Overcome," Vivian says he saw something remarkable.
"I turned and looked at Dr. King and he was very quiet, he was very still. And a single tear ran down his cheek."
Almost 50 years later, Vivian is experiencing another surge of emotions over voting rights. He looks remarkably the same, and his preaching voice is still intact. He says Section 5 is needed because the country has become even more racially divided after electing its first black president.
Vivian says the fate of the Voting Rights Act shouldn't be left to nine judges who never walked in a place like Selma. He says only those victims of discrimination who benefited from Section 5 "have a right to say that things have changed enough to get rid of it."
The image remains chilling even after almost 50 years.
It is a "missing" poster distributed by the FBI in the summer of 1964. It shows the faded, black-and-white photos of three civil rights workers -- James Earl Chaney, Michael Schwerner and Andrew Goodman -- who were reported missing in Mississippi.
We now know what happened to those men. They were arrested by Mississippi sheriffs, let out of jail, and ambushed on a rural road where they were beaten and shot to death. Their story was made into a grossly inaccurate Hollywood movie called "Mississippi Burning."
Still, many people forget today why those three men were murdered: They were trying to register black voters.
Rita Schwerner Bender cannot forget. She is the widow of one of those men. She was married to Schwerener, then a 25-year-old New Yorker who had decided to travel south to help register black voters. Both were part of an interracial group of college students who organized black residents for a project known as Mississippi Freedom Summer.
It was an audacious plan. They were black and white and working side by side in a region where races were often kept apart by violence. They established "Freedom Schools" to teach black students shunned by the state school system and even established a Mississippi Freedom Party that crashed the 1964 Democratic National Convention to challenge the state's all-white delegation.
Bender is not sure that many younger Americans know anything about Freedom Summer.
"Certainly people who are probably under the age of 35 or 40 don't have a personal sense of the struggle that occurred," she says.
Bender is currently a partner in the law firm of Skellenger Bender in Seattle. She heard the argument that Supreme Court Justice Scalia made when he said that the Voting Rights Act had become a "racial entitlement."
"I can't think of a more offensive statement .." she says. "I'm feeling pretty angry. When I hear a statement like that, it's quite abusive."
Bender, however, will not show much emotion when talking about her days in the voting rights movement. She won't talk about the loss of her husband. She weighs every word and speaks in a monotone about that violent period in her life.
Asked how her parents reacted to her becoming a civil rights activist, she paused before saying: