If you found President Obama's Oval Office address a bit disappointing, as I and many others did, it's worth reading this item by Charles Homans at Foreign Policy, which adds some useful historical context for environmental types frustrated that the president didn't commit to passing a cap-and-trade bill. The take-away: Earlier man-made environmental disasters--Homans cites the deadly Bhopal chemical leak in 1984--eventually spurred major legislation of the sort that Obama seems to be flinching from:

The BP spill has certainly recast public opinion on oil drilling, but its implications for broader environmental policy, particularly a future energy and climate change bill, are far from clear. ... But keep an eye on what comes out of today's hearing. [Henry] Waxman and his House colleagues are less central to the future of a climate bill than their opposites in the Senate, or the president. Still, the guy knows how to make use of a disaster.

Sure enough, at just about the time Homans posted this item, Rep. Joe Barton (R-Texas) was apologizing to BP for making them pay for the oil spill. Barton's astonishing actions certainly could shift the debate in the direction of stronger legislation. We'll have to see. But Homans's post, and the Barton episode, are a reminder that not all policy derives from the words and actions of the guy sitting in the Oval Office.