Mrs. Michelle Malkin has posted[1] a remarkable example of the harm that political correctness can do to society. Political correctness is an interesting way to silence dissent and mandate censorship, as no one likes to be called racist, sexist, so on. People will flee these emotionally charged labels so fast that they will often give in rather than attempt to debate the accuracy of the label. Indeed, in today's atmosphere, an attempt to debate it rather than fleeing tends to exacerbate the harm done in the minds of the listeners, who are unlikely to engage the issue rationally.
[1] http://michellemalkin.com/archives/002394.htm