He's been doing it for a few weeks...
But there are some folks in Washington who see things differently. (Boos.) You know what I’m talking about. (Applause.) When it comes to just about everything we’ve done to strengthen our middle class, to rebuild our economy, almost every Republican in Congress says no. (Boos.) Even on things we usually agree on, they say no. If I said the sky was blue, they say no. (Laughter and applause.) If I said fish live in the sea, they’d say no. (Laughter.) They just think it’s better to score political points before an election than to solve problems. So they said no to help for small businesses, even when the small businesses said we desperately need this. This used to be their key constituency, they said. They said no. No to middle-class tax cuts. They say they’re for tax cuts; I say, okay, let’s give tax cuts to the middle class. No. (Laughter.)
http://obama-mamas.com/blog/?p=1885