Yglesias lists some bullet points:
President Barack Obama ... will get a terrible week or two of press but should actually benefit politically (cold comfort for the damage it will do to his substantive agenda). It’s much easier to complain about “Republican obstructionism” if Republicans have the 41 votes they need to obstruct. Similarly, it’s easier to keep your coalition together if it’s not possible to do anything.
At least the phony war will be over. Reform versus nihilism would be a good position for Obama to campaign on in the mid-terms.