One of the marks of a sociopath and a pathological liar is that they'll often lie even when: (1) they are lying about something that can easily be verified as false; and (2) they lie about a situation in which it does absolutely no harm to tell the truth.
The recent history of the Clinton family is littered with examples of both.
I used to work in prisons. I'm very familiar with the type.
I remember it was George Will who said: Bill Clinton may not be the worst president every, but he is the worst person to become president.
Great line.