Kill off the entire population of the world except for you. Short of having only one inhabitant, nothing can prevent all terrorism. They, the terrorist, is fighting for an idea. Tim McVey was a terrorist.
The only thing that makes us civilized are laws. Realizing that I'd rather obey the law than go to jail. If I didn't care about the results of my actions then I'm freed to do whatever I want.
If a terrorist is willing to die for his beliefs, then war won't stop him. Neither will police action. Believing that any agency could infiltrate all organizations and prevent further terroristic actions in an exercise in fantasy. There will always be terrorists.
A War on Terrorism is ludicrious. Unless the War is only a front to restrict our freedoms. "We're at war, therefore ...". A war must be against a country with whom we can negotiate a ending. ObL cannot end the terrorism. So we cannot declare "war" on ObL.
When will Schrub declare "peace"? Week after his reselection?