Former GOP presidential candidate Herman Cain waves at a rally the College of Charleston on January 20, 2012. Comedian Stephen Colbert held the event with Cain, titled "Rock Me Like a Herman Cain South Cain-olina Primary Rally", as part of his pseudo-run for president of "The United States of South Carolina." Richard Ellis/Getty Images hide caption

itoggle caption Richard Ellis/Getty Images

Comedian Stephen Colbert, left, holds a rally with former GOP presidential candidate Herman Cain at the College of Charleston in South Carolina. Richard Ellis/Getty Images hide caption

itoggle caption Richard Ellis/Getty Images

Former House speaker Newt Gingrich (right) and Herman Cain during a Republican presidential debate Nov. 22, 2011, in Washington, D.C. Mandel Ngan/AFP/Getty Images hide caption

itoggle caption Mandel Ngan/AFP/Getty Images

Republican presidential candidate, Herman Cain campaigned Wednesday in Dayton, Ohio. He told a Fox News interviewer he would decide in the next week whether to stay in the GOP race. Al Behrman/AP hide caption

itoggle caption Al Behrman/AP

Hillary Clinton's "inevitability" became less certain after a debate in Philadelphia at Drexel University in October 2007. William Thomas Cain/Getty Images hide caption

itoggle caption William Thomas Cain/Getty Images

Republican Presidential candidate Herman Cain greets supporters at a campaign rally outside of Wings Plus on Wednesday in Coral Springs, Fla. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

Republican presidential candidates jockeyed for airtime when they met for their first prime time TV debate on Saturday night in South Carolina. Alex Wong/Getty Images hide caption

itoggle caption Alex Wong/Getty Images