exhaei. hido50 eto m >>> democrats hillary clinton and bernie sanders go head to head in their fifth debate tonight, the first since martin o'malley dropped out of the race. but, as weijia jiang reports, the leading republicans are still battling over victories in iowa. >> reporter: republican senator 10 crews -- ted cruz met with potential voters saturday. while he continues his work with donald trump. interested in a temper tantrum, or you could call it, a trumpertantrum. >> reporter: in a series of tweets, donald trump accused ted cruz of fraud in the iowa caucuses. the republican party disagreed and made the results official. overnight, trump to do it again, suggesting cruz's tactic was a misdemeanor at minimum. >> these politicians are brutal. >> reporter: democrats hillary clinton and bernie sanders are preparing for debate tonight, the first head-to-head showdown since martin o'malley dropped out of the race. at a town hall event last night, the candidates continue to spar over which o