>Tomorrow night, in his 20 minute address to the nation, will President Obama go big? Or will he go small? Will he use the auspicious moment to argue for the imperative of carbon pricing, or will he greet the nation by announcing new regulations on part of the energy sector?

The President has said that he would rather be a one termer who gets big things done than he would avoid the burden of presidential leadership. He's given one speech on climate change recently. That speech was ... a speech. A good speech, but a speech. No follow through, publicly or privately. If he means what he says, he will Go Big.

A senior administration official to whom I put the question this morning responded that Obama recognizes that the moment to assert his command over the disaster that is the BP oil spill has passed. Another official said Obama will use the time to "go Big. That's where he does best."

Details are not protuberant from the West Wing. It may well be that Obama has not yet decided how he wants to use his first Oval Office address. It is clear that the American people want to hear something from him. The White House believes that they don't want a lament. They certainly won't mind a little blame-casting. Officials are preparing new rules for the energy sector, but it's hard to imagine that Obama would borrow our ears to tell us about new regulations, chapter and verse.

If Obama goes big, there is really only one way he can attempt it: he must call on Congress to put a price on carbon by the end of the year. The pivot from gushing oil to climate change is at once harder than it seems and blindingly obvious. Oil is polluting the Gulf; it's not raising temperatures. The transition to a more ecologically friendly economy will require carbon creation. It will also require economic sacrifice.

Given the demise of the tri-partisan climate change bill in the Senate, the chances of finding 60 senators to vote for a cap-and-trade bill of any sort seem slim. Democrats as friendly to the President as Sherrod Brown of Ohio and Claire McCaskill of Missouri aren't going to help foster a transition from dirty to clean energy when their own states must keep those dirty energy jobs around. On Thursday, Senate Democrats plan to decide how to proceed on climate change. No one expects them to choose the bolder options.

If Obama went big, the political ramifications would be serious and unpredictable. The Senate and House campaign committees would plotz. He would face vociferous opposition from members of his own party; David Axelrod would have a call sheet 50 pages long from consultants who want to know whether he is out of his mind. These people want Obama to talk about jobs, and jobs only. Getting a climate bill would require both the power of presidential persuasion and a hefty amount of behind-the-scenes maneuvering. (Sherrod Brown would receive weekly phone calls from Rahm Emanuel asking him what it would take to get his vote.) There is no good political reason to go Big. (I tend to believe that the political repercussions of pressing for a climate bill would not be nearly as disadvantageous as one presumes; on the one hand, presidential approval ratings tend to influence the performance of a president's party; on the other, candidates now have a handy way to distance themselves from the president.)

But, at times, the President has different equities than members of his party. This is one of them. Figuring out how to solve this existential problem is on Obama's shoulders, not Congress's, really. Climate change denialism is rising, and no one on the President's level is fighting back. The chances of building a consensus for climate change legislation will not be helped by the addition of a few Republican senators. More vulnerable Democrats are up for re-election in 2012 than in 2010. If now isn't the right moment, there may never be a better one.

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