One note of disagreement: I don't think Obama should be campaigning today - in fact one might argue this is a case where he can campaign by not campaigning. What I mean is that Romney has pretty much embarrassed himself today by playing politics with this issue. If I was an adviser I'd suggest Obama cancel all his rally plans for today and hold his own press conference, and implicitly state he has no intention of discussing politics; no need to attack Romney or even mention his name, Romney has done enough damage to himself today.
By holding a 30 minute press conference and discussing this issue as well as the Israel situation, Obama will look far more presidential than the shit Romney pulled today. Hence the idea of campaigning by not campaigning. He doesn't have to hold a rally - or even mention Romney's name - to do damage