I think Obama could be helped if he comes out strongly against the court for this and other bad rulings. 80% of Americans oppose Citizens United, and 65% strongly oppose it. How many issues have 65% of Americans strongly on the same side? Today's court would still rule 5-4 for Bush v. Gore. The court needs to branded the activist right-wingers that they are.
Of course if Obama just tepidly criticizes it, this will help Romney.
In theory every year the supreme court could be challenged for being to ideologically to the left or right. Do you know why it's not challenged? Because its political suicide for a president to challenge the courts. It's one thing to challenge congress for being to concerned with their party because of re elections but its another thing to challenge the Court who has no incentive to appeal to any party considering they're in office for life.
It's one thing to have your bill stuck down but it's another thing to try and attack the court. The former might let you break even but the latter will lose you support fast even among your own party. A president criticizing the court for ruling a controversial bill unconstitutional, goes against the whole idea of separation of powers, no one wants a president overstepping his boundaries.
Not really overstepping a line with criticism. Obama already criticized the Supreme Court after Citizens United and no one cared. Obama's approvals are higher than theirs.
http://www.nytimes.com/2012/06/08/us/politics/44-percent-of-americans-approve-of-supreme-court-in-new-poll.html?pagewanted=all