At a time of national-security crisis, Kerry planned to coast into the White House on his autobiography as a war hero. Against weak opposition, he quickly wrapped up the Democratic nomination, and no one–either opponents or the press–bothered to question the story he told about himself.

Then, once the general-election campaign was under way, the Swift Boat Veterans for Truth came along to dispute his accounts of his own heroism and to remind Americans that Kerry’s first foray into political life consisted of Senate testimony in which he viciously slandered fellow veterans. Kerry had no good response–in part because the Swift Boat Vets had him dead to rights, at least on the latter point, and in part because he was unprepared…

By attacking now, Gingrich ensures that it won’t be the first voters hear about the matter, which will take some of the sting out of the Obama attacks. He’s also acting as a proxy for the president–call him Barack Hussein Gingrich–giving Romney the chance to practice and improve his defense, something he unquestionably needs to do.

Contrariwise, if Romney is incapable of learning to defend himself effectively, Republicans are better off learning that now, while there’s still time to nominate someone else.