It now appears that the strongest lines of attack against Fred Thompson will focus on his work as a lobbyist--and, in particular, some of the clients he may or may not have represented.
Witness an LA Times story (later picked up by the AP) claiming Thompson did lobbying work for a pro-abortion organization in 1991.
Now, leave aside the fact that this was in 1991--back before a 1994 survey where he allegedly took a pro-choice stance, which isn't that big a deal (all sides are in agreement that he has long since taken a strong and consistent pro-life position). Nonetheless, NewsBusters tears the story to shreds.
(They also note that the people making these claims about Thompson have ties to the campaign of a certain other presidential candidate. Three guesses who that candidate is, and the first two don't count.)