This country has been more than willing to support some truly disgusting people and their causes because they were perceived to be our allies. Our backing of murderous undemocratic foreign governments and terrorist groups whose goals align with ours is one of the main catalysts for encouraging terrorist behavior aimed at us and our interests. When we support groups and governments who have no trouble starving, torturing and killing civilians, those civilians have a legitimate beef with us. When we continue to make sure that these same people cannot legally change their government, history shows that they will rise up in arms.
For most of the 20th century we were able to avoid the fate of the european powers that did the same thing (partly through our use of client states,and partly because of favorable geography). This will not continue. OBL is just one of the first terrorist leaders to realize what a what an easy target we are in a globalized world. There will be much more to come, because we seem to be unable to change our imperious behavior.
Europe got tired of being victims of terrorism and changed their global behavior accordingly. We will probably not do the same because conservatives have managed to drown out any legitmate debate over the issue, just like with the War on Drugs (which actually funds many of our terrorist enemies). Using zero tolerance, with us or against us policies engen
ders the very behavior that we are trying to eradicate. This country simply doesn't seem to have the brain power required to think beyond one or two steps of cause and effect.
We have got to break the cycle of trying to run the world like our playground, and then being surprised when we have to deal with the blowback. I don't know how we get there, but I think one of the first steps is realizing that the enemy of our enemy of our enemy is not always our friend.