[American Constitutionalist]

" Wood would be willing to do it for free, for the simple reason that high profile cases are millions of dollars of future business.
Plus, he’d get a really nifty write-off. "

and a chance to Mike Nifong the witch. i.e. get her disbarred and discredit her and Cain's accusers....

[Jonty30]

Many good reasons.