This seat's taken

The Mormon dimwit Mitt Romney invited Clint Eastwood to ramble on incoherently at the Republic convention. The actor decided to speak to an empty chair, as if it were occupied by Barack Obama.

Obama replied to Eastwood and Romney by means of a marvelous three-word tweet and photo:

It's an excellent example of the effectiveness of imaginative tweeting. The power of such a message, today, is equivalent to what would have been obtained in the old days (before the Internet) by a vast and costly billboard campaign.