Vast majority of voters are “idiots” to various extents (i.e. voters tend to be far from the ideal of a rational, informed voter), so depending on what kind of voters you’re appealing to, you would say different kinds of half-truths or lies.
Because if saying some half-truths or lies increases the votes you get, then due to the simple goal of maximising your chance to defeat your political opponent, you will need to lie to some extent.
So even politicians with the best of intentions would perform some degree of lying, depending on how “idiotic” the voters are.
E.g. in the present US presidential election, Donald Trump is clearly trying to get votes from the more idiotic side of the US population, while Hillary Clinton is generally trying to appeal to the less idiotic side. So Trump would naturally be lying a lot, and saying even some outrageous things that actually appeal to the idiots whose votes he is targeting.
Perhaps Trump may not even really care about whether he wins or loses the election, because there are plenty of ways for him to make more money out of all the publicity, etc., that has been generated.