Republican presidential hopeful Herman Cain will decide "before Monday" on whether to quit the race for the White House as claims of a 13-year affair threatened to end a campaign dogged by sex scandals. Cain, once the front-runner to take on President Barack Obama in November 2012 elections, has denied wrongdoing, saying he was only friends with his latest accuser, Ginger White, who says they had a sexual relationship. "Before Monday we'll make a decision," Cain said in an interview on Fox News late Thursday, admitting that a flurry of allegations of misconduct had sent his presidential bid "off message."...