South Carolina Democratic primary

Hillary Clinton takes a selfie with a supporter in Fairfield, Ala., where she held a campaign rally Saturday before heading to South Carolina for her primary night event.

People arrive to vote in the South Carolina Democratic primary in Columbia.

A woman votes in the South Carolina Democratic presidential primary.

Rapper Killer Mike greets Democratic presidential candidate Bernie Sanders at a campaign rally in Columbia, S.C.  (Jacquelyn Martin / Associated Press)

Hillary Clinton greets restaurant patrons in Birmingham, Ala. She made campaign stops in Alabama on Saturday before traveling to South Carolina for her campaign night event.

A polling station official holds “I Voted” stickers at the Prince Hall Masonic Lodge during the South Carolina Democratic presidential primary on Feb. 27, 2016, in Columbia.