Andrew Young, a civil rights "trailblazer" will endorse Wesley Clark on Dec. 21 in South Carolina:

Young's ties to the glory days of the civil rights movement may help Clark, a neophyte to American politics, in the black communities.

About half of all Democratic voters in South Carolina are black. Minorities play major roles in several other primary and caucus states, including New Mexico, Michigan and Arizona.

Some background on Andrew Young:

Young, 71, was a congressman, U.S. ambassador to the United Nations, Atlanta's mayor for two terms and a gubernatorial candidate in 1990, losing to Zell Miller in a primary runoff. Young's rise to prominence began in the civil rights struggle, when he was a top lieutenant of the Rev. Martin Luther King Jr. His election to Congress in 1972 made him the first black elected to Congress from Georgia since Reconstruction.