Why attacking Romney on Bain now will hurt him later

First, the attacks seek to undermine the core of Mr. Romney’s brand.

Mr. Romney has made his private-sector experience a major theme of his campaign, using it to form a contrast to the “career politicians” he is running against in the primary as well as to Mr. Obama. “I think to create jobs it helps to have had a job,” Mr. Romney has said repeatedly. He has argued for less government regulation of private enterprise, and has said he would repeal new regulations on financial companies.

It would be one thing if the substance of the attacks on Mr. Romney had to do with an ethical problem at Bain Capital or some type of personal association. This is not to say that voters would have no right to consider the issue, but it would be somewhat peripheral to the core economic message of Mr. Romney’s campaign.

But these attacks take a different tack. They are a critique of Bain Capital’s business model and, by extension, a critique of a certain form of free-market activity that Mr. Romney and other Republicans advocate.