NINE OR TEN YEARS….Commenting on Gen. David Petraeus’s view that we’ll need to stay in Iraq for nine or ten years, Matt Yglesias says:

It really is striking how un-optimistic the more optimistic views of Iraq are when you get down to it. Michael O’Hanlon thinks our strategy “probably can’t succeed” unless the political situation in Iraq magically alters. General Petraeus thinks he’s making so much progress that the war will need to continue twice as long again as it’s already gone on.

Right. And as long we’re bringing O’Hanlon into the picture, here’s what he says:

Over the long term, the United States must be looking to draw down its force levels in Iraq overall — probably to 100,000 or fewer troops — by about 2010/2011.

If O’Hanlon thinks that by 2011 we’ll only have drawn down to 100,000 troops, that suggests he doesn’t think total withdrawal will happen until, say, 2016/17 or so. In other words, nine or ten years.

Matt says that’s so far out that it’s crazy to even pretend we can forecast what will happen. But it’s actually worse than that. Consider two other big counterinsurgency wars that were going badly after a few years: Vietnam in 1964 and Afghanistan in 1984. In both cases, the entangled superpower had the option of either pulling out and taking its lumps or extending the conflict, and in both cases it made the choice to extend the conflict. And both times that was the wrong decision. Staying in Vietnam did immense long-term damage to the national security of both Southeast Asia and the United States, and staying in Afghanistan was a leading cause of the eventual collapse of the Soviet Union. For both countries, staying involved in a long and deadly counterinsurgency almost certainly did far more harm than pulling out would have.

So if you had to guess whether another five or ten years would be good or bad for the United States, the odds say it will be bad. Very, very bad.