Obama opposed the war. But the war is all but over. What remains is an Iraq turned from aggressive, hostile power in the heart of the Middle East to an emerging democracy openly allied with the United States. No president would want to be responsible for undoing that success.
This account of the situation in Iraq sounds precisely like what Peter Galbraith predicts in his book Unintended Consequences: How the War in Iraq Strengthened America's Enemies, as described in Michiko Kakutani's review:
The “pretense that the surge is a success and that therefore the United States is winning the Iraq War,” Mr. Galbraith contends, “is the opening salvo in a coming blame game as to who lost Iraq.” He suggests that the surge has enabled President Bush to “run out the clock on his term in office so as to avoid having to admit defeat” and that running out the clock serves the interests of the Republican Party, setting up a G.O.P. story line for 2009: “When George W. Bush left office, America was winning the Iraq War. His successor — abetted by the Democratic Congress and the faithless American people — squandered the victory and is responsible for the consequences.”
Krauthammer seems to be setting up exactly the narrative that Galbraith predicted Republicans would concoct: W. had things under control, so any future successes must be a result of W.'s vision, whereas any future failures can be ascribed to Obama's and the Democrats' craven altering of that vision.
Krauthammer writes, "The Democrats now own Iraq. They own the war on al-Qaeda." Well, yes, but who got us into the mess in Iraq in the first place? And since when is it the war on al-Qaeda? Bush made it the war on terror, and that broad formulation allowed him to take the war to Iraq, which he'd wanted to do even before 9/11. Krauthammer is trying to blur our memories of the past in order to cast a more forgiving light on Bush's administration.