I have read that Lt. Col. John Nagl is leaving the Army. He is the author of the Army's new Counterinsurgency Manual, and of the interestingly-titled book, Learning to Eat Soup With a Knife. He also appeared on The Daily Show and was interesting and actually pretty funny.
To the extent that there is any basis to the claim that things have gotten better in Iraq, it is almost certainly due to the counterinsurgency strategies developed by Nagl, and probably does not have much of anything to do with "the surge." Thus, his leaving the Army is a big deal.
I see that he is going to work for a "think tank" called the Center for a New American Security. This is a "centrist", Democratic-leaning organization primarily made up of people who held foreign policy and defense positions in the Clinton Administration. This might suggest something about Nagl's party affiliation.
The timing of Nagl's departure might also suggest that he intends to become involved with one of the campaigns. I would be curious to know if any of the Democratic candidates have courted him. He would do a great deal to bring national security credibility to a Democrat's candidacy.