This post by Josh Marshall says something that is in a way obvious, but well, I've never seen it so cogently and perfectly stated before.
Here are the paragraphs that whapped me upside the head:
"And here I think we get back to the root of the matter: We are bigger than Iraq.
By that I do not mean we, as America, are bigger or better than Iraq as a country. I mean that that sum of our national existence is not bound up in what happens there. The country will go on. Whatever happens, we'll recover from it. And whatever might happen, there are things that matter much more to this country's future -- like whether we have a functioning military any more, whether our economy is wrecked, whether this country tears itself apart over this catastrophe. But we'll go on and look back at this and judge what happened.
Not so for the president. For him, this is it. He's not bigger than this. His entire legacy as president is bound up in Iraq. Which is another way of saying that his legacy is pretty clearly an irrecoverable shambles. That is why, as the folly of the enterprise becomes more clear, he must continually puff it up into more and more melodramatic and world-historical dimensions. A century long ideological struggle and the like. For the president a one in a thousand shot at some better outcome is well worth it, no matter what the cost. Because at least that's a one in a thousand shot at not ending his presidency with the crushing verdict history now has in store. It's also worth just letting things keep on going as they are forever because, like Micawber, something better might turn up. Going double or nothing by expanding the war into Iran might be worth it too for the same reason. For him, how can it get worse?
And when you boil all this down what it comes down to is that the president now has very different interests than the country he purports to lead."