For a while now, I've been remarking to anyone who will pretend to listen on how postmodernism is fast becoming an instrument of evil. Observe the following claim in this thread I stumbled across regarding American violations of the Geneva Conventions:

Under the customs of war, not civil law, these are matters for the military command to decide. Thats my opinion, with historical precedent. You could disagree, but there really isn't anyone with authority who can say which of us is correct.

Or, as a galloping idiot told me during a discussion on Wikipedia:

There is no absolute certainty in the factuality of evolution. It is subject to replacement just as the original theories of atomic structures were. There are many problems with the theory itself which tend to make it slide a little off its high horse.

Or, the parody version, courtesy of the Daily Show

Jon: ...that's just innuendo and that can't be the only thing in a news story.
Colbert: Can't it? I ask you: DOES Jon Stewart orally pleasure teamsters for pocket change?
Jon: Uhhh, no.
Colbert: Well, you are certainly entitled to that opinion, but I'm sure I can assemble an impressive panel who thinks you do. The truth lies somewhere in between. Let's talk about it for eight weeks, and let the public decide.

In other words, the inchoate nature of knowledge has become a shield for the ignorant. Though I haven't got many specific examples on hand, I'm sure that you can dredge up anecdotal memories of application of such arguments to modern political topics. I've long felt that postmodernism was something of a nihilistic tradition, and even if it can serve as a basis for attacking regressive dogmatic moral positions (e.g. Christian patriarchy), it doesn't leave anything of worth in its place, and can be applied equally blindly in attacking progressive stances. And as it becomes an ever more deeply embedded mode of thought, its use in that manner will only become more frequent. 'Ware being hoisted by your own petard.