Rumsfeld was an avid supporter of special-operations forces (SOF). Against Navy resistance, he led the effort to refit ballistic-missile submarines with SEAL delivery vehicles in place of Trident nuclear warheads, to make it easier to land special operators on beachheads. His passion for SOF was shared by a number of Democrats, including Senators Carl Levin, John Kerry, and Jack Reed. With Congress's support, Rumsfeld got SOF's budget doubled, from $3.5 billion to $7 billion: proof that just because Donald Rumsfeld believed something, didn't mean it was wrong.
Where Rumsfeld's shortcoming were and part/or maybe much of what led to his demise was his understanding(lack of) of COIN by 2004. His idea of handling this red headed step child of warfare was to treat it as a low level task and drop it off in the lap of a much dismayed USSOC. At that point USSOC understood that the immensity of developing a COIN strategy was not understood or appreciated by Rumsfeld, and began to keep their distance.
Those interested, a very informative read What Rumsfeld Got Right
ALSO!! - An hour with Counterinsurgency expert David Kilcullen with Charlie Rose
I am a fan of Rumsfeld but he had some very serious shortcomings