Was the surge needed?

I’m talking about the Iraq “surge” of course; the magic answer to all war-ills brandished by John McCain during his campaign. I’m not trying to say that now things are quiet and boring in and around Baghdad; there’s still plenty of violence to go around and probably will be for quite sometime. I don’t believe the 20,000 extra troops deployed in 2007 actually calmed things down in Iraq; instead, I think that it was a combination of good timing and changing circumstances. One was the cease-fire by Moqtada al-Sadr and his Mahi militia, another was the alliance from Sunni fighters with the US forces in an effort to quick some thugs out and finally a US assassination campaign against extremist leaders also played a significant role in the drop of violence. The largest contributor to that trend however was probably the systematic ethnic cleansing of Iraqi neighborhoods. At the time the surge came on the scene, there was almost no one left to be killed, hence the relative improvement. To add another contrarian view to the surge, some analysts like Steven Simon on the Council on Foreign Relations argue that the methods used in it were unsustainable and might have actually decreased the prospect for a stable Iraq in the long term.