Did Post-Modernism Spawn Rhetorical Use of History

Ralph E. Luker makes an interesting point in a recent post at Cliopatria:

What interests me about the way Churchill, Malkin, and some of Churchill's apologists use history is that if you can find a precedent for an action in the past (Malkin's Japanese internment; Churchill on Lord Amherst's use of smallpox) it becomes, on the one hand, a convenient excuse for similar action in the present; or, on the other hand, justification for blatant distortion of history because we know that there was holocaust intent anyway. Proyect makes his support of Churchill's holocaust argument quite explicit here. If you doubt it, you are a 'holocaust denier' and, yet, Proyect is finally persuaded that, in this case, the evidence denies it. Think about it. If past precedent justifies present action or blatant distortion of the historical record, we can repeat the 19th and 20th century's horrors; and we have, indeed, bought the post-modern notion that all the world's merely a text, to be construed as we will.

I think he's on to something, but I'd add that sometimes the political use of history is not so much done as a reinterpretive excercise as an obfuscating, or ignorant, one. (See below).