Now, some Iraq-watcher friends of mine point out that this is absurd. "Sadr is, of course, a thug," they say, "but he's a nationalist. And he's far less beholden to Iran than the Islamic Supreme Council of Iraq or Maliki's Da'wa Party -- both of whom we're supporting! And most importantly, Sadr remains perhaps the most popular figure in Shiite Iraq. Petraeus can do business with him. This doesn't make any sense!" And they're right. It doesn't. But as long as we sponsor the Iraqi political process -- and a Sadrist doesn't actually become premier himself -- this will keep happening.
And another option would be to... stop being the sponsor.