David Frum: "It's a wild gamble, undertaken by our oldest ever first-time candidate for president in hopes of changing the board of this election campaign. Maybe it will work. But maybe (and at least as likely) it will reinforce a theme that I'd be pounding home if I were the Obama campaign: that it's John McCain for all his white hair who represents the risky choice, while it is Barack Obama who offers cautious, steady, predictable governance."