FILE - In this March 11, 1988, file photo, Democratic presidential candidate Gary Hart waves to supporters at a news conference in Denver, after announcing he would withdraw from the 1988 presidential race for the second time. At his side is his wife, Lee. Herman Cain drew a line in the sand, and now he has to hope it sets like concrete. Cain, a surprise leader in recent Republican presidential polls, has responded to allegations of sexual harassment with a series of definitive statements that invite closer scrutiny of his past conduct. Any number of politicians past were derailed after issuing a public invitation to check out their conduct, none more famously than Hart. (AP Photo/Aaron E. Tomlinson, File)