This sounds pretty convincing to me. It seems to me that a harder line policy vis-à-vis Iran probably would have been desirable at one time, but the upshot of the Iraq War has been to increase our need to secure Iranian cooperation on some regional issues while drastically reducing our "hard power" leverage relative to Teheran. Under the circumstances, though an engagement policy is unlikely to produce any really fantastic outcomes it seems preferable to the alternatives of drift or conflict. I'm open to persuasion on this front, though, not someone with really firm Iran-related convictions. Mostly I have deep suspicions about the motives and methods of the Iran hawks, though I'll admit to the possibility that they've somehow stumbled on the right idea through an unsound method if someone can make that case.