> That gives me hope for humanity.

As long as there are less than nineteen people in the pool...

I'm not exactly sure if that should or not.

There have been any number of leaders that have been horrible people and yet the average normal people excuse their behaviors, and some even buy into their behaviors.

Depends on how much those 5% procreate compared to others.

Should be quite a lot, evolutionarily speaking.

Being a horrible manipulative jerk seems like a great reproduction strategy to me.

On average women will see through you and won't give you the time of day. Some will fall for your terrible abusive manipulation, though.

They get impregnated and you move on. Your victims will on average have the usual mothering instincts and will do their best to help their kid make it. Eventually, that should result in you generating many offspring.

I hope this strategy isn't conscious on anyone's part, but it sounds like one evolution would reward.

I hope someone can show me a fatal flaw in my reasoning.

This assumes that it is a heritable trait. My anecdotal experience leads me to doubt that.

Do those 5% vote in each and every primary election ?

No, they run in them.