http://en.wikipedia.org/wiki/The_Pentagons_New_Map from Thomas PM Barnett is probably the "official" version of this -- a small, lethal military designed to win wars, and a "SysAdmin force" designed to build nations after the fact.
I'm not sure how well this theory has held up (it's from 2004...), or how much support it has. I think what happened is we got lucky in Iraq in 2007-2010 using the old British strategy of allying with semi-enemies against real enemies (Sons of Iraq and the other Sunni tribes, and non-aggression with the Shia militias), eked out a borderline draw in Iraq while calling it "a victory for COIN", applied the "COIN" model rather than the "British" model to Afghanistan with the surge and all, and have proceeded to lose from 2009-now in Afghanistan.
I'm not sure how well this theory has held up (it's from 2004...), or how much support it has. I think what happened is we got lucky in Iraq in 2007-2010 using the old British strategy of allying with semi-enemies against real enemies (Sons of Iraq and the other Sunni tribes, and non-aggression with the Shia militias), eked out a borderline draw in Iraq while calling it "a victory for COIN", applied the "COIN" model rather than the "British" model to Afghanistan with the surge and all, and have proceeded to lose from 2009-now in Afghanistan.