If the goal of terrorism is to trigger fear and irrational behavior, the 911 actions were pretty successful.
Dead in 911: Around 3000. (Approximately the same number as weekly traffic deaths in North America).
Dead from how the US responded: Hundreds of thousands, perhaps up to or more than a million.
US military spending since 911: 6.6 trillion dollars.
Source: Wired – The Dead, the Dollars, the Drones: 9/11 Era by the Numbers.
The terrorists themselves can only make sure their initial operation is successful. The rest is up to us. And in this case, the US has done a very good job in (a) ignoring far more important issues (e.g. sustainability, a more real/deep democracy) and (b) bankrupting themselves through military spending, as the Soviet Union did before them.
Some stories for me to look at:
The US people are profoundly irrational.
The media doesn’t focus on what’s really important.
People do things that’s not in their own interest.
Americans think they have the best society in the world, while it’s flawed in so many areas.
They are terrorists.