Goblins. It was goblins what did 9/11.

Seriously though, I've yet to come across the government which has the competence to run over a dog and make it look like an accident, nevermind one which would successfully be able to get the tens of thousands of people a conspiracy on the scale of 9/11 would require to play along, keep their stories straight, and have no smoking guns be revealed. Seriously. The US government can pull all this off, keep thousands of people quiet, convince the entire planet's mainstream media that it was someone else's doing, but their genius plot is going to be unravelled by some kid?

Also if the government really did kill 3,000 people, I'm fairly sure they're not going to have a problem with doing in some punk from Colorado or whereever who unfurls their masterful scheme.