Victorious In Spite Of Themselves?

Very interesting thought from a Powerline reader relative to our being on the cusp of victory. He compares the Iraq war to Sherman's march on Atlanta:
the [Atlanta] campaign was originally conceived to complement what was intended to be the “decision” (decisive operations) in the East by Grant’s forces then operating against Lee’s Army of Northern Virginia. As the year wore on with little progress in Virginia, horrific casualties, and an election looming against emboldened, conciliatory Copperhead Democrats, the Union Cause was in great jeopardy. Grant, bogged down around Petersburg, wrote Sherman that "the decision would have to come in the West." After frenetic maneuvering and a few relatively small-scale but decisive battles, Sherman was at last able to capture Atlanta. Union morale was restored and the war was over approximately six months later. No one expected at the beginning of the Atlanta campaign that it would be the year's decisive operation and the death knell of the Confederacy.

I think this is illustrative of what has taken place in Iraq against Al Qaeda. For years now we have been expecting that the decision against Al Qaeda would occur in the East, in Afghanistan. OIF was expected to complement world-wide efforts against state-sponsored terrorism, but not to defeat Al Qaeda per se. As it has transpired, however, it turns out that the decision against Al Qaeda has occurred in the West – in Iraq, both physically and morally, with global ramifications that we will be assessing and (hopefully) exploiting for the next few years.
I have to think about it, but it sounds right. Here's a discussion question for you, from the Devil's Advocate, who's sitting right beside me. Would Bush have fired the old generals, hired Petraeus and "surged" without media focus on casualties, a looming bad election and the emboldened defeatism of the Left? In other words, was it precisely impending defeat that caused Bush to double down and make a last ditch effort for victory --knowing that with the whole world against him, he basically had 6 months to turn things around? To what extent do we owe the defeat of al-Qaeda to Harry Reid, et al, saying it couldn't be done?