For Obama, the worst result next month might be for Democrats to retain control of both houses of Congress. If they do, their majorities will be paralyzingly small. And their remaining moderates will be more resistant to the liberal leadership: The moderates will have survived not because of, but in spite of, those leaders.
Today, if you see Obama in a political ad, you are almost certainly watching a Republican ad. And a recent NBC/Wall Street Journal poll shows that more than twice as many people view House Speaker Nancy Pelosi negatively (50 percent) than positively (22 percent).
If Democrats retain control of Congress, Obama will seek re-election while being perceived as responsible for everything in Washington, where everything is perceived to be dysfunctional. And anti-Washington fever may be worse than it is today, because the 2010 elections will not seem to have changed very much.
If Democrats lose both houses, Obama will seem repudiated. If they lose neither, he will seem impotent. So, if Democrats lose big, he loses big. If they lose smaller, he loses bigger.