Actually Obama's camp might well be considered a likely culprit. Clinton's camp would gain nothing but grief from doing this, and given the Enquirer's apparent owner's links to Clinton, whoever did leak it knew Clinton would be blamed first.
I agree with your assertion that this probably doesn't matter much, but the timing (perfect) intrigues me and makes me wonder if Barack Hussein hasn't decided to show the Clintons he can play hardball too. OTOH you could also argue Edwards leaked a fake story on himself since in terms of the tracking polls he would be the most helped by it if it's shown or believed to be false.
“OTOH you could also argue Edwards leaked a fake story on himself since in terms of the tracking polls he would be the most helped by it if it’s shown or believed to be false.”
But if it comes to be known that someone in the Edwards camp leaked the story, it would look worse on Edwards...