"Romney has no core"

Before the Herman Cain snafu (show me on the doll where Herman Cain tried to hire you), the big story was the Obama campaign going negative on Romney, trying to define him as flip flopper à la Bush v Kerry. It's about building a narrative and casting the election as a contest of values.

But it's also about preempting what Romney's campaign must necessarily do in the coming months. The president's advantage over the Republicans (and those are few and far between in this economy) is that he has no primary, while the Republicans duke it out over who is Most Conservative®. Candidates running in a primary always follow the same playbook. Cultivate that base during the primary, and hurry toward to the center for the general. By driving home the point right now that Romney is an opportunist, the Obama campaign hopes to handicap Romney's ability to shift positions in the general, which candidates are always wont to do, and Romney the political chameleon perhaps even more so than the average pol. So this puts Romney between a rock and a hard place: does he morph back into a moderate (again) as any candidate would in the general and risk playing into the Obama campaign's central criticism of his character - or does he stand firm, refuse to walk back the extreme positions he's staked out during the primary and risk losing the center?

It's a good set-up if Team BO pulls it off, and it looks like it's working. Since the last Republican debate, Romney opened himself up to this line of attack by suggesting that he wouldn't hire illegal immigrants because he's running for office, and then wiggled his way out of his previous support for an Ohio union-busting measure that looked sure to lose (and indeed failed badly today).