I'm working on a theory. It goes something like this:
1) High-status males (or alpha males, or dudes with big egos and powerful personalities, whatever you want to call them) tend to cheat on their spouses/partners. Not because they are intrinsically less virtuous than the rest of us, but because they are presented with many, many more opportunities to do so, particularly from high-status (read: attractive) females.
2) Most (successful) men in politics are high-status males.
3) Ergo, most men in politics cheat on their spouses.
4) Being caught cheating on your spouse often (though certainly not always) brings a political career to a close, or at least derails higher ambitions.
5) Proposed: Men who are successful at the highest levels of politics tend to not only to be liars and cheaters, but those who are very, very good at lying and cheating.
None of this is intended to excuse, dismiss, or minimize the behavior of any individual. Nor is it to say that we shouldn't concern ourselves with the moral fiber of those we put in power over us. I just wonder if by drumming out all of the inept cheaters in politics we aren't running a sort of moral/political Dosadi Experiment.