An email:

I am British (although I live in the US), so perhaps not be as practiced as I ought to be in parsing meaning out of American writings, but my first thought on reading Novak’s lines was that the Senators fear the administration clinging on and the end result being blame for the military, rather than a deliberate plan to run out the clock in order to blame the military. It seems to me that, as you say, the administration will also get fingered if the military cannot sustain the effort. It seems to me that Novak is saying that some Senators fear that not only does Bush realise the seriousness of the situation, but that as as result of that, he’ll run the clock out whilst blithely hoping for the best.
I would be concerned, myself, that the military will at least lose some lustre as a result of the feared scenario and, unlike the administration who will all be off doing something else in a few years, the military will still be around and dealing with the aftereffects, on recruitment, on public support and (perhaps most importantly, given the potential longevity of the effect) on the positive effects on the morale of their enemies. A US military breakdown, if it were to happen, would be fantastic news for the bad guys, even better than a US withdrawal. The latter could at least look like an unwillingness to pay the price necessary; the former would announce actual defeat in reality.
That was my reading of the Novak article, more or less, based on a similar analysis to yours (ie, the administration can’t be *planning* to run the clock down and hightail it, because it would harm them, too). I do think that the administration are throwing the dice, however; in some sense, they may feel that they have no choice. People who are looking further ahead than the administration might be looking, they can feel that the administration’s gamble may not be worthwhile in the long term even though all the alternatives look pretty bad, too.