As the saying goes, Islamic extremists hate us as much for who we are as for what we do. They despise our culture. As a result, it makes perfect sense to talk about a clash of civilizations as it pertains to them.
But they don’t count for much after the destruction of ISIS. Iran isn’t really a revolutionary state anymore, and its appeal is limited to Shiite Muslims. Afghanistan is a basket case; it is debatable whether its leaders have much interest in spreading the word outside its boundaries in any event. The principal Islamic states dislike jihadis as much as we do. There just isn’t much fuel available for an international culture war between Christians and Muslims; the more prominent dispute is the centuries-old internal battle between Sunnis and Shiites.
Once again, the clash of civilizations thesis fails the reality test.