As a counter to Barack Obama's call to tear down walls, it would help to review the e-mail from a Marine printed in Andrew Sullivan's column in The Atlantic Magazine April 30, 2007.
"But speaking of counter-insurgency, much of the success in Al Anbar in the last 5-6 months has to do with the US Marine Corps' back-to-basics counter-insurgency effort. In the Hadithah Triad for instance, 2nd Battalion 3rd Marines focused our efforts on limiting the insurgents' freedom of movement which has long given the insurgent his center of gravity - freedom of action. We bermed the towns of Hadithah, Haqlaniyah, Bani Dahir, and Barwanah and stopped vehicle traffic. These simple actions, which the US military is well equipped to carry out with existing assets and skill sets, crippled the insurgency in our portion of the Western Euphrates river valley, forcing many Sunni insurgents and AQI affiliated groups to the periphery of our battlespace or else to other cities. Predictably, attacks plummeted in our area of operations as the insurgent, unable to move about freely and anonymously in his vehicles of choice - the ubiquitous four door sedan and/or Kia bongo pickup truck - could no longer transport men and material. These foundational COIN precepts have also been employed in other Anbari cities with varying degrees of success; we were able to do it all and reaped the most success. That is not to toot our horn but only to point out that where our Corps is able to focus enough assets and attention, this basic counter-insurgency plan of action can be carried out with relative ease. Without the basic conditions of security and stability enshrined in an area, you can not began to hope for locals to take the reins and began running their locality, much less an entire country."
The building of berms in late 2006 (i.e. before "the Surge") was essential to beginning the Anbar Awakening. This is quite different to Oama's revisionist history in Berlin.