Timothy Noah, writing in The New Republic, suggests that getting a Supreme Court ruling before the 2012 election could help President Obama’s re-election prospects, regardless of which way the Court rules.
Surely from a political standpoint, President Obama is smart to press the Supreme Court  for a health care decision this coming June, no? If the Court upholds Obamacare then we will all be reminded that this sole accomplishment makes Obama the most consequential Democrat since Lyndon Johnson to occupy the Oval Office.... But slapping down a sitting president in a transparently partisan manner with a decision that did violence to eight decades of jurisprudence and that would literally cost American lives--yes, I think a “no” vote would be a pretty bad way for the Court to go--would be a fantastically effective way to "energize the base," as we say in Washington, and maybe rope in some independents, too.
But Noah is only looking at the liberal side of the ledger. The people who give the most thought to the constitutionality of the Affordable Care Act are conservatives. And they are adamantly opposed to it. A ruling upholding health care reform would surely rile up the Republican base.
A ruling against the law would presumably only overturn the individual mandate, and would only win with a 5-4 margin. That gives Republicans have three powerful arguments to make to their base about the importance of the election: Obama does not respect the Constitution, it is very important to control future Supreme Court appointments, and it is important to control Congress and the White House to determine the fate of the rest of the law.
On policy grounds I think it was wise for Obama to ask for a ruling from the Court as soon as possible. Politically, I think it’s a toss-up.