From Chief Rabbi Lord Jonathan Sacks:
Two things have haunted me since 9/11. The first is the pain, the grief, the lives lost and families devastated, the sheer barbaric ingenuity of evil. The scar in our humanity is still unhealed. The second is our failure to understand what Osama bin Laden was saying about the West. We did not hear the message then. I’m not sure we hear it now.
After the shock and grief subsided, two theories began to be heard. The first was that this was an event of epoch-changing magnitude. The terms of international politics had been transformed. The Cold War was over. Another war had begun. This time the enemy was not the Soviet Union and communism. It was radical, political Islam.
The second was the opposite. 9/11 was terrifying and terrible but it changed nothing because acts of terror never do. Terrorist campaigns have been aimed at other countries. Britain suffered similarly from the IRA in the 1970s. The most important thing is not to overreact. Terror may bring dividends in local conflicts but it never succeeds in its larger political aims.
There is something to be said for both theories. But there is a third, no less consequential. Why did al-Qaeda attack America? Because it believed that it could. Because it thought the US was a power past its prime, no longer as lean and hungry as it believed it was.