Thompson? Class-Card? Why?

I saw a recent online article that read something like "Huckabee and Thompson Playing the Class Card against Mitt." One can hardly imagine why Fred Thompson would do so. His father may not have been the CEO of a Detroit car company (he may have only run a dealership), but it isn't like Fred Thompson's story is a Dickens-esque, rags-to-riches narrative. His father may not have been rich, but his father-in-law (by way of a shotgun wedding) could apparently pay for him to go to Vanderbilt School of Law. Thompson may have had a part-time job on a factory floor, but he's the only person I can think of whose financial situation was improved by getting someone pregnant.