A former Dallas county sheriff, Jim Clark, whose violent confrontations with voting rights marchers in Selma, Ala., shocked America in 1965 and gave momentum to the civil rights movement, died Monday at 84 in Montgomery, Ala.

Clark, who wore a “Never” button on his sheriff ‘s uniform to show his opposition to black voter registration, was voted out of office in 1966, in large measure because of opposition from newly registered black voters. Throughout his life he maintained he had done the right thing in 1965.

He and his deputies joined state troopers in attacking marchers on the Edmund Pettus Bridge in March of that year, an event that became known as “Bloody Sunday.” It prompted the Rev. Martin Luther King Jr. to lead a voting rights march from Selma to Montgomery and got Congress to pass the Voting Rights Act, which did away with many segregationist practices that made it difficult for blacks to vote.

“He was a very, very mean man. His meanness really served simply to express the subtle evil of the system of segregation,” the former Atlanta mayor who organized voter registration efforts in Selma in 1965, Andrew Young, said.

In a 2006 interview with the Montgomery Advertiser, Clark said, “Basically, I’d do the same thing today if I had to do it all over again. I did what I thought was right to uphold the law.”