Max Boot waxes historical:
There is a lesson to be learned here by advocates of an American troop drawdown. Even if the drawdown were to be only partial, it could easily get out of hand by creating the perception that we’re on the way out and can be attacked with impunity. As Napoleon said, “In war, moral considerations account for three-quarters, the actual balance of forces only for the other quarter.” If we set a withdrawal timetable, the moral balance will tip against us even faster than the actual balance of forces—with deadly consequences.
Mona at Unqualified Offerings notes the potentially salient point that Napoleon lost the war. Moral factors, it turns out, couldn't compensate for the fact that Russia is very big, extremely cold in the wintertime, and pretty far from France. The Emperor could, presumably, console himself with the thought that his forces weren't so much defeated on the battlefield as that their supply-lines became untenable, but these kind of hair-splitting distinctions are of limited comfort when you're in retreat.
Boot, though, takes the analogy in another direction, citing the O'Pollahan op-ed from yesterday and hailing it as "pretty significant coming from two Democratic analysts" when it was more like drearily predictable.