There are two kinds of liars. First, there's the

Opportunistic Liar, like Robert Novak, who

who could tell the truth if he wanted to.

Second, there's the Pathological Liar, like

Robert Novak, who couldn't tell the truth

even if he wanted to.

Robert Novak is at it again. This time he has outed

Peter Potamus, an underwater CIA operative.