Interesting article today in the NY Times about the on-going terrorist threat.  This is the relevant passage:

Classified investigations of the Qaeda threat now under way at the F.B.I. and C.I.A. have concluded that the war in Afghanistan failed to diminish the threat to the United States, the officials said. Instead, the war might have complicated counterterrorism efforts by dispersing potential attackers across a wider geographic area.

So why exactly did we go to war against the Taliban?