The latest liberal meme is that McCain talks about his POW experience too much.
Bingo. With sufficient media control this actually confers the ability to dictate one's opponent's message. Those days are gone, but al-Reuters is the last to know.
It cuts both ways, too, if the ground is properly prepared. Obama's godhead is a particularly corrosive little meme of its own. That sort of thing works best when your opponent does it to himself.