Donald Trump and Marco Rubio continue their attacks on Ted Cruz's integrity in campaign's final hours.Voting is under way in the South Carolina Republican primary, where frontrunner Donald Trump hopes to overcome a slide in the polls and Ted Cruz is hoping for a repeat of a performance in Iowa, where he defied polls and defeated Trump by 4 points. Votes will be cast until 7 p.m. Saturday. At stake in the first of the Southern primaries are 50 delegates. * Check back here for live voting results as they come in. Nevada Democrats were also caucusing Saturday, where Hillary...