Ron Paul has been booed a few times in the Republican debates, primarily for saying things every expert knows and the whole world considers Americans slightly deranged for trying not to know.
What the booers don’t bother to consider is this: what other candidate, with his rehearsed and focus-group-tested answers at the ready, would even consider saying something that might slightly displease his audience, much less cause them to boo? Are you sure the best person is the one who spends his speaking time flattering you, and saying what he thinks you want to hear?
It seems to me that a person who says things he knows will elicit hostility, but says them anyway and is not dissuaded even while being booed on national television, may actually be the man of principle and determination that the other candidates can only pretend to be.