In theory, there are two negative frames that fit Mitt Romney: 1. He is a politician of rare expediency, who changes his positions even on matters of deep principle; and 2. He is a right-wing conservative. The Obama campaign has placed its bets on the latter characterization, reasoning that it will cut more with independent voters. Moreover, it worries that the flip-flop story line could have unintended consequences by perversely reassuring some voters that Romney's conservative horns are not really all that sharp.

However, the more you know and see of Romney, the more his actions fit the flip-flop frame. Take the latest embarrassment over his decision to call the health-care mandate a tax, having defended it for years as a "penalty." The penalty argument served Romney well in Massachusetts, where he instituted a mandate to buy health insurance that became the model for the Affordable Care Act.  But now that Romney has morphed from chief architect to chief critic of the mandate, a penalty has become a tax.

  This is the pattern with Romney: seismic shifts in his political core — on abortion, global warming, health care. But Romney's moral flexibility extends to other aspects of his life.  A current Vanity Fair article contains a small, but meaningful anecdote about Romney's  days at Bain, where he advised a first-year employee to obtain information about the firm's competitors by lying. Let that roll around in your head for a minute: a boss telling a subordinate to lie. That's a pretty bright line to cross, and it suggests that Romney may have lost his ethical bearings early on.