Frank Underwood, I can't help but wonder... how is it that the lead character of a show, a man who will literally lie, cheat and steal his way into the White House, maintains popularity with the show's fans? Spacey's character is unquestionably a sociopath or, if you prefer, afflicted with antisocial personality disorder. At times he strategically all-but-admits his sociopathy to other characters as a tool to win back their trust.
I've seen studies that indicate that people are quite good at spotting sociopaths, but if the sociopath is sufficiently charming will nonetheless allow themselves to succumb to his charms and confidence. Plenty of people saw through Bernie Madoff, but plenty more chose not to. I guess if you're smooth enough, charming enough, we can find a way to turn off our better judgment.