As the economy weakens and the campaign intensifies, we'll hear more of James Carville's familiar refrain: It's the economy, stupid. Well, it ain't — or, at least, shouldn't be. I'm not claiming that Carville is wrong about voting. People vote their pocketbooks. In the latest Washington Post-ABC News poll, the economy overshadows Iraq as the most important issue by a 39% to 19% margin. What I'm saying is that this sort of voting is shortsighted. It rewards or punishes candidates for something beyond their power. We have a $14 trillion economy. The idea that presidents can control it lies between...