By putting themselves into the political spotlight, the SwiftVets have become “public figures.” Most of the spin being put out by Kerry and his allies falls into the category of statements of opinion, rather than fact. And even allegations of pure fact would have to be proved not only false, but made with “actual malice” to permit a recovery for defamation.

So threat letters notwithstanding, nobody’s going to sue anybody in a serious way for defamation (libel or slander). If they do, almost any judge would recognize it as a ploy to conduct political warfare by other means. I doubt either side could get to the subpoena-and-deposition stage.

And actually, in a democracy, that’s exactly the way it should be. This ought to play out in the court of public affairs.