I am not an attorney; I got this information from the Expert Law website.
This is just a layman's speculation, but it seems to me that Griffin could be found culpable of libel for these reasons:
- He was given a chance to retract his statement and apologize; he did not take it.
- He continues to opine that his statement was and is true, in spite of denials by the Palins and an apparent lack of any proof, though he may still present evidence at trial;
- His malice towards Palin is well documented at his own blog, where he constantly insults her, pushes conspiracy theories (like the Trig birth smear) and wishes her bodily harm, specifically, that she fall off the curb and break an ankle. (There may be more examples, I have not exhaustively searched his blog. You can bet that Palin's attorneys have, however.)
Litigation is a crap shoot. You can never tell where a judge or jury will come down on an issue; however, Griffin would do himself a favor by apologizing, retracting his statement and moving on.
Related: Both Stacy McCain at The Other McCain and Dan Riehl at Riehl World View have coordinated their efforts to investigate Jesse Griffin. They imply that they have uncovered information of great interest but are checking with an attorney before publishing it.
Another Black Conservative has summarized the events leading to the outting of Alaskan Blogger Jesse Griffin; it's an informative read.