Past performance is no guarantee of future results:
This leave-them-guessing strategy slips out in [The Audacity of Hope's] prologue. "I serve as a blank screen," Obama writes, "on which people of vastly different political stripes project their own views." He notifies readers that "my treatment of the issues is often partial and incomplete." It takes some doing for a politician to write a 364-page book, his second volume, and skate past all controversy.
— "Obama Scores as Exotic Who Says Nothing," Froma Harrop, Real Clear Politics, December 26, 2006.
— Headline at Twitchy, today.
Update: Speaking of past performance being no guarantee of future results, Jim Treacher proffers "A tale of two press conferences," asking, "Why is President Barack Obama so much angrier and more animated about losing a Senate vote than about somebody bombing the Boston Marathon?"
Yes, it's a rhetorical question.