In Postmodernism Jameson talks about the Vietnam conflict: 'this first terrible postmodernist war cannot be told in any of the traditional paradigms of war novel or movie--indeed, the breakdown of any shared narrative paradigms is, along with the breakdown of any shared language through which a veteran might convey such experience ... may be said to open up the place of a whole new reflexivity' [pp.44-45].
Would Jameson talk about the war this way, I wonder, if the USA had won it? (Strawman whispers: "But then it would have fitted the narrative paradigm of colonial conquest and oppression!"; so, in what way does the war not fit the paradigm of postcolonial resistance?)
There's a danger that 'America' has so interpenetrated the discourse, and indeed ideology, of 'success' that the mere fact that American here lost construes this war as unusually terrible, disjunctive and therefore as a uniquely postmodern conflict.