from Christopher Hitchens, in Slate. An excerpt:
The most obvious points of comparison would be these: Both movements are based on a cult of murderous violence that exalts death and destruction and despises the life of the mind. ("Death to the intellect! Long live death!" as Gen. Francisco Franco's sidekick Gonzalo Queipo de Llano so pithily phrased it.) Both are hostile to modernity (except when it comes to the pursuit of weapons), and both are bitterly nostalgic for past empires and lost glories. Both are obsessed with real and imagined "humiliations" and thirsty for revenge. Both are chronically infected with the toxin of anti-Jewish paranoia (interestingly, also, with its milder cousin, anti-Freemason paranoia). Both are inclined to leader worship and to the exclusive stress on the power of one great book. Both have a strong commitment to sexual repression -- especially to the repression of any sexual "deviance" -- and to its counterparts the subordination of the female and contempt for the feminine. Both despise art and literature as symptoms of degeneracy and decadence; both burn books and destroy museums and treasures.
I think he treats the other similarity -- both are repressive of political, religious, and social dissent -- as too obvious to need mentioning. He also goes on to acknowledge differences, related to corporatism and racial superiority (though suggests that Islamofascism does in some measure involve some claims of racial or ethnic superiority).