There's an active debate going on between Andrew Sullivan and Josh Marshall on one side, and Max Boot, on the other, about whether the current occupation of Iraq can meaningfully and usefully be compared to the U.S.'s historical occupation of Germany after WWII.
To begin with, it's worth noting that any historical analogy can be illuminating up to a point, and thereafter is misleading. The key analytical question in the use of historical analogies, is whether the historical similarities are more revealing than the historical dissimilarities are misleading.
In the comparison of the current Iraq occupation to the post-WWII German or Japanese occupation, it seems to me as if the dissimilarities far outweigh the similarities. The ongoing combat situation in Iraq is one key dissimilarity, which most of the Marshall-Sullivan-Boot discussions has focused on.
But another key dissimilarity is that for Germany, the occupation was tolerated by the local population and elites in large measure because they were afraid that a worse occupier--namely, the Soviet Union--was the only other option. No such more pernicious occupier threatens Iraq. Indeed, the key "outside force" that the U.S. is worried about, namely Iran, is one that many if not most Iraqis regard as a preferable partner to the U.S. This was certainly not the case in Germany.