Of course, Michael O'Hanlon spent a week in Iraq and says these guys are wrong:
Viewed from Iraq at the tail end of a 15-month deployment, the political debate in Washington is indeed surreal. Counterinsurgency is, by definition, a competition between insurgents and counterinsurgents for the control and support of a population. To believe that Americans, with an occupying force that long ago outlived its reluctant welcome, can win over a recalcitrant local population and win this counterinsurgency is far-fetched. As responsible infantrymen and noncommissioned officers with the 82nd Airborne Division soon heading back home, we are skeptical of recent press coverage portraying the conflict as increasingly manageable and feel it has neglected the mounting civil, political and social unrest we see every day. (Obviously, these are our personal views and should not be seen as official within our chain of command.)
Obviously, the other side of this debate is going to be able to produce its own group of soldiers to back them up, but the basic claim these guys are making is more logical than factual: "Counterinsurgency is, by definition, a competition between insurgents and counterinsurgents for the control and support of a population." As they say, it's simply implausible on its face to think that better tactics and an increase in the level of troops from way, way, way fewer than history deems necessary for this sort of thing to way, way fewer than history deems necessary for this sort of thing could reverse the fact that the US troop presence lost the support of the population years before the surge began.