One of the difficulties that Obama had in dealing with Romney is that at their core, Romney's proposals are a shell game. On most issues he has different positions or promises that are inconsistent, either blatantly or subtly. When attacked on one, he asserts an inconsistent or incompatible one—the one his current audience wants to hear, he thinks.
Make no mistake, Romney is a clever deceiver. That is because he creates so much confusion that he is hard to get a handle on. The best approach is what the late Ted Kennedy did, to start by calling him 'multiple choice,' by revealing the game that he is playing.
For example Romney made very clear that he has contempt for the 47%. He has also said that he cares for the 100%. Which one is the real Romney? We don't know, but we do know that at least one of them is lying.
Will Obama expose the game tomorrow night? I'm afraid the presidency may hang on it.