Can you name one national election won recently by a Republican who didn't lie?
Romney, Gingrich, and Santorum are all W Bush Republicans. Each would skyrocket spending given the chance. For example, Santorum voted for the most expensive liberal entitlement in over 30 years: prescription drug coverage for seniors. He's running as a "conservative". Watch the actions, not the words. GOP words are lies usually.
Republicans who have a chance of winning rely on the Reagan tactic of promising low taxes, spending more than Democrats, and hoping they are dead before the poop hits the fan and we are like Greece.
Democrats at least have Bill Clinton, who governed as a moderate, reformed welfare (Reagan and H W Bush didn't), and balanced the budget. If you are extremely partisan and not too smart, you may claim that lying about sex is anywhere near as bad as Iran/Contra. It's not.