Whelan can’t jump back across the defamation line through his retraction, either. While his mea culpa and tweet deletions will make it harder for people to find the assailant’s identity, it’s not that hard. (It took me exactly four seconds.) In any case, the law is clear that the defamation is actionable once “published”—meaning, made known to at least one other party. Here, of course, the whole Twitter-verse watched, agape, as Whelan pumped out his “what if” account.
Whelan’s retraction could still be relevant, though, in another way. The law presumes that, at least in cases of libel (written defamation, which includes Twitter), the plaintiff has suffered harm, so recovery of damages is possible even if no calculable damages—such as the loss of one’s job—are proved. But since the jurors have a good deal of discretion in fixing the amount of the award, they are quite likely to award less compensation in cases, like this one, where there’s been a retraction and an apology.
Some have mentioned another possible claim. A number of states recognize a claim with less stringent requirements than defamation against anyone who places the plaintiff in a “false light” that would be “highly offensive to a reasonable person.”