STUFF YOU SHOULD READ

Once in a while, I'll recommend a full article.

Here's one now:
THE INVENTION OF FLIP-FLOP.
Fictional Character,
by Jonathan Chait for
The New Republic

Money quote:

This is not to say Kerry is some sort of natural plebeian. Of course he's not. The point is that unflattering characterizations of Kerry and other Democrats tend to find far wider circulation than equally unflattering characterizations of Bush.

... with plenty of examples and a very good explanation provided.