Law, religion and politics were the preeminent themes in the American civil rights movement, a former student activist told an audience of about 40 at the Institute of Politics on Tuesday.

Jack Chatfield, who worked for the Student Non-Violent Coordinating Committee (SNCC) in the 1960s, said the Supreme Court's Brown v. Board of Education ruling initiated the civil rights movement.

"It was a blow to a southern white culture rooted in the dim and dark days of slavery," Chatfield said of the decision, which banned segregation in public schools.

But the ruling triggered a new wave of violence among white southerners, said Chatfield, who is presently an associate professor of History and American studies at Trinity College.

Chatfield pointed to a 1955 incident when a Black teenager "was whistling or maybe made a veiled sexual remark at a white woman."

Chatfield said the youth was taken from his grandmother's home in the middle of the night and was thrown into a river.

"This hardly marked the mood of the white South as a whole, but it signalled what might happen if the social system was challenged," Chatfield said.

He pointed to the Constitution's interstate commerce clause--which gives Congress the right to regulate trade among states--as the grounding point for much civil rights legislation.

Congress, Chatfield said, drew upon the interstate commerce clause when enacting laws such as the landmark Civil Rights Act of 1964.

"The commerce clause, as innocuous, as bland as it is, packs a keg of dynamite," he said.

The second theme of the civil rights movement, Chatfield said, was religion.

He said that the liberal and change-oriented civil rights movement was "saturated with religious character, with religious value and with religious music."

This, Chatfield said, contrasts sharply with today's politics, in which fundamentalists stand at the right of the political spectrum and seek to ban abortion and exclude gays.

Indeed, the music of the early 1960s gave the civil rights movement energy, Chatfield said. And that music, he added, "all came out of the Black Gospel tradition."

Politics was also a motif of the civil rights movement, Chatfield said.