The attack could prove sticky, for three reasons. First, it takes Mr. Romney’s central rationale as a candidate and turns it into a bludgeoning tool. Mr. Romney, after all, is the guy who knows all about turnarounds, which is why we’re supposed to hire him as our c.e.o. Every day he is forced to defend his business record, as opposed to his stance on abortion or gun control, is a bad day for Mitt Romney.

Second, it casts doubt on Mr. Romney’s aura of electability. Most independent voters may not be ready to take up signs and occupy the local park, but neither are they feeling especially warmly toward Wall Street speculators and bonus-gobbling chief executives at the moment, and the Bain narrative casts Mr. Romney in exactly this light.

And third, the Bain line of attack, more than anything else brandished against Mr. Romney to this point, might bring to the surface an instinctive concern that he’s emotively challenged. I heard some version of this a lot when I visited conservative activists and operatives in South Carolina a few weeks ago — that Mr. Romney seemed plastic and programmed, an impression that could only be exacerbated by the idea that he was laying people off and sleeping just fine.