“Political correctness is just tyranny with manners. Charlton Heston
This is as good a definition as I have ever heard of the phenomena. The definition at Wikipedia goes on for almost 3200 words. The thing that bothers me most about the inroads of PC is how utterly destructive and unforgiving it is. Whole careers are destroy by a single offensive statement and no common apology or moderate act of repentence is enough. PC is the Queen of Hearts on steroids (somebody ought to get her tested), “Off with their heads!” Zero tolerance eventually breeds nuclear responses to popgun problems and when intolerance is uncovered it is intolerantly addressed, an oxymoron if there ever was one.