> What distinguishes involuntary falsehoods (e.g., misquoting someone unintentionally, or basing an argument on data later proved to be false) from lies in this case?

For the vast majority of people (even those who consider themselves apolitical), it will be how much they like the politician in question. My side? Definitely just being misquoted, or taken out of context, or an honest mistake. The other side? A crazed partisan intentionally manipulating the system, a terrible excuse for a human being, and should be jailed before being summarily executed.