With the phenomena of radical Islam, however, we are confronted with the phenomena of individuals and groups who value a self-destructive fantasy more than their lives and interests. The presumption self-intrest is no longer valid when dealing with many parts of the Islamic world. This realization is tremendously disorienting for a typical Westerner
I disagree. The problem with the critique of realpolitik in this article is that it takes a much more narrow definition of "rational actors" than is really necessary. "Rational actors" are basically defined as "people like us", or more specifically, people who will ultimately value self-preservation above all else, just as we do.
Which is, to be sure, pretty much what the classic notion of realpolitik was based on - you could bluster people into submission, because you knew that, faced with the choice of accepting defeat or dying, they would accept defeat and opt for self-preservation. But that's no reason to think that the concepts can't be expanded to encompass what we're facing now.
And what we're confronted with now is a culture that has arrived at precisely the opposite set of values than what we're used to - given the choice between submission (i.e., failing to advance their own interests) and death, they would rather die. But this is a value choice, and no more or less rational than the opting for self-preservation in the face of certain defeat that we would choose. Admittedly, it's very much an all-or-nothing proposition for them - either they get what they want, or die trying - but it's a perfectly rational calculus at work here, albeit not the sort of calculus we are used to dealing with.
So we're still confronted with rational actors, but actors for whom submission is not an option. And it goes too far to define that sort of value choice as prima facie "irrational", IMO - all value choices are, to some extent, not subject to rational bases. We tend to think that it's better to be alive than dead, but I think that given a moment's reflection, you might find that it's actually very difficult to put together a rational foundation underlying that choice other than that it's simply your personal preference - in a very real sense, saying that being alive is better than being dead is not at all different than saying that chocolate ice cream is better than vanilla. No matter how much poking and prodding you do, you're going to end up with the same basis in purely personal preference for both of those choices.
So where do we go from here? Well, realpolitik is far from dead - we just have to recognize and understand the sorts of rationality at work in the minds of those who would destroy us. They still have interests, and act in furtherance of those interests, but part of their rational calculation is the conclusion that it's better to be dead than submit. And so if deterrence won't serve to rein in their actions, then we simply take the next logical step and kill them before they kill us - which was always a final option held in reserve under the notion of realpolitik. QED.
So, although it may very well appear that I end up in much the same place as the author, I think I do so by rather a different route. I very much dispute the notion that a "new paradigm" is necessary or desirable, particularly when the old one is still perfectly serviceable, given a bit of tweaking. And isn't that the essence of conservatism? ;)