On the other hand, if American forces were to leave Iraq now, the likely result would be an escalating civil war that would radicalize Iraq's Shiites, leaving Sadr and his ilk in control of either the whole country or its Shiite-majority region--along with most of its oil. That would give Ahmadinejad's Iran a chain of likeminded governments stretching from Afghanistan's western border to Lebanon's Bekaa Valley. A jihadist Shiite superpower with nuclear capability at the head of such an alliance is a truly terrible outcome, comparable in world-historical terms to Hitlerite rule over Europe. It is well worth fighting to prevent this--indeed, it is worth fighting harder than America has fought to date.First off, note that the rationale for the war has switched once again. Rather than worrying that Osama bin Laden will take over Iraq if we leave, we're supposed to worry that Iran will. And, it must be said, this new concern is considerably more plausible than the old one. Indeed, this very possibility was widely cited as a reason not to invade and topple Saddam Hussein's regime. What I don't understand is what we're supposed to do about it. If the Iraqi public by and large prefers to be governed by Iranian-linked Islamist political parties, stationing a giant block of American soldiers in the country isn't really going to alter that. Conversely, insofar as the Iraqi public by and large doesn't want to be governed by Iranian-linked Islamist political parties, then it would be extremely difficult for Iran to establish that sort of domination.
What's more, the whole "chain of likeminded governments" concept is in desperate need of some further analysis. The entire NATO alliance is composed of "likeminded governments" featuring a much higher degree of policy coordination than Iran and Syria. Nevertheless, Canada and Italy, or the United States and Belgium, still are separate countries, not a single unified menace. In practice, it's difficult for authoritarian regimes to sustain intimate cooperation over an extended period of time (the lack of transparency reduces trust and makes it hard to commit credibly) and it seems very unlikely that a unified Iran-Iraq-Syria bloc could remain intact for long. Look at the history of the ill-fated union between Syria and Egypt and you'll see that this is an inherently problematic idea.
--Matthew Yglesias
