Comment by femto

> and their fall kicked off the decline

My feeling is that the response was the thing that kicked off the decline. At the time of the attack, the US had quite a bit of goodwill around the world. The US could have surgically gone after the people responsible, with minimum civilian deaths, and most of the world would have backed them to the hilt, and the US would have come out stronger. Instead we had spurious claims of weapons of mass destruction, the coalition of the "willing" going into Iraq with jackboots on, over the widespread objections of their own populations, and abuses in Guantanamo Bay. That response burned an awful lot of goodwill around the world: which kicked off the decline.