Having been peripherally involved in a trade dress lawsuit through a former employer, I'm extremely familiar with the phrase "confusingly similar," and as questionable as Wikipedia can be at times, that is an accurate cite of the Lanham Acts.
Those knock-off books could be removed from all shelves, and all marketing halted by injunction, until the dispute is settled ... it would take years.
Perhaps a lawyer advising Governor Palin is smart enough to understand that a lawsuit and the resulting publicity is the only way Betsy Reed is ever going to sell more that five or ten thousand of her book (which she admits is largely a compilation of previously published material)?
BTW, what kind of self-respecting radical lefty goes by the name Betsy? I once had a feminist try to tell me that Betsy Ross was sleeping with George Washinton and advising him on military strategy during the Revolution, so that could be part of it.