Here's Hitchens's latest and reportedly last take on Amis's book:
http://www.guardian.co.uk/g2/story/0,3604,785574,00.html
"I am glad I didn't try to tell you any more about Rosa Luxemburg, who was probably more of a historical heroine to us, not least because her warnings about Leninism had been the earliest, not to say the most lucid and courageous. But then one had to face the argument that if she and her comrades had been more ruthless and more Leninist, the militarist German right might have been crushed in 1919 instead of, with infinitely more suffering and woe, in 1945. This is and was a deeply serious and troubling question (though I must say that its least serious consequence is that you have pissed me off by making light of it)."