It is sad and tragic that this happened but it is time to face reality.
The War On Terror is being hopelessly lost and another course must be
considered. Any zealot with a few bags of fertilizer or a can of gasoline can kill many as long as he doesn't value his own life. Often he is raised in hopeless poverty and ignorance and can easily be made a tool or weapon of arseholes who control him. The answer is never simple but it must start by raising the standard of living and the education of people in the third world. This may require a whole generation or more to pass, and probably reducing the wealth of some nations in order to share the world's resources with the world's people. Democracy means little to one who has never known it. An empty belly means little to one who has never known it. Religion promises a better life dead than alive so the answer for too many is an act of desperation.