Ad Hoc Definition Syndrome

I've decided to start collecting instances of a few categories of characteristic left-wing logical and rhetorical habits.

Here's a fine post over at Tom Hamilton's Let's Be Sensible, concerning some "anti-war left" rhetoric about "moral agency". The whole thing is worth reading, but the AHDS outbreak appears early, in the quoted text:

...the contention that terrorists are possessed of 'moral agency', i.e. they possess the capacity to make rational, self-interested moral judgements and take actions which are in accordance with morality...

Hamilton writes that this sentence "...shows one of the strangest understandings of the concept of moral agency I've ever seen." It does indeed, but it's not really an "understanding of moral agency"; it's a a refusal to admit that the concept of moral agency even exists, a refusal so forceful that the writer insists that the very phrase actually refers to something else.

The punchline is that this "definition" of moral agency, this "dangerous bullshit" that our lefty ascribes to the Diabolical Pro-War Left, approximates the very common anti-war left belief that violent Islamists are in fact acting rationally and morally, in their own accurately-perceived self-interest, and can therefore be negotiated with. It is axiomatic to (much of) the anti-war left that all of Osama bin Laden's demands on the West are reasonable, and that bin Laden can be trusted to honor any bargain we strike with him. I have personal doubts about the wisdom of any policy that relies on the infallible wisdom and sweet reasonableness of a religious fanatic who massacres civilians for a living, but maybe that's just me.

Then again, our lefty loses interest in this ridiculous "definition" almost immediately (I don't blame him; it's useless for his purposes). When he goes into detail about why the pro-war left are wrong to believe it, he starts accusing them of other things entirely. Hamilton goes over all that in detail; read it, it's good.

UPDATE 8/10/2005: Added "(much of)" to the stentorian "It is axiomatic..." line, because somebody in comments pointed out that, erm, well, it's really not quite all of them, is it? Quite a few, certainly, but not all.