COLUMBIA, SC - JANUARY 18, 2016: Democratic presidential candidate, former Maryland Gov. Martin O'Malley marches in the King Day at the Dome parade at the S.C. State House Monday, January 18, 2016 in Columbia, South Carolina. The event drew appearances from Democratic presidential candidates Sen. Bernie Sanders, I-Vt, former Maryland Gov. Martin O'Malley and Hillary Clinton. (Photo by Sean Rayford/Getty Images)