Here’s Kagan’s take on the new realism. The 21th century may well morph into one dominated by autocratic empires that achieve economic prosperity and techno-military power without much personal freedom. The state isn’t withering away anywhere but in Europe. Will the Europeans come out of their postpolitical fantasy to meet the challenges of Russia, China, and so forth? These challenges probably dwarf the one posed by radical Islam, unless an Islamic tyrant rises up with the Machiavellian qualities of, say, Putin. So those who prattle on about the universal victory of liberal democracy or spin libertarian dreams about apolitical globalization will be more and more out of touch. (It goes without saying that I’ve state this thesis provocatively for your consideration.)
Peter here I think Kagan is trying to push the thesis of his new book a little too hard. The whole issue of Islamic terror has to do with the danger that totalitarian/terror based regimes have on the workings on the rationalist state actor model that realism assumes. Here Kagan needs to read Hannah Arendt's Origins of Totalitarianism because she explains what makes 'Realism' vulnerable and unable to deal with a totalitarian regime. What Islamic extremism is is what Arendt would call a totalitarian movement and what it is in search of is a state which will give it more power to act on the world stage.
Here Kagan fails to see what is going on. The problem is that totalitarianism has not disappeared, it has altered forms and new forms have emerged. But this new conflict is enacting itself over the former ideological conflict of communism, which although defeated on one level is still alive and well in the hearts of those who are ruling a few states. Now China is not so much totalitarian, but retains the instruments of totalitarian power at the services of ruling party and military elite that uses it to keep control of the goodies. In Russia, one can see Putin as those former Soviet elites following the Chinese model and reasserting control via terror. The problem here is more of belief, that the actors don't believe in the ideals of the Soviet regime, they only want the powerful tools and instruments that system had at its disposal.