Whatever objectives those involved in the attacks on the World Trade Centre and the Pentagon on September 11 wanted to achieve could not have justified their suicidal missions, which killed more than 6,000 innocent civilians.
But the 5,000 protesters who descended on Washington yesterday - and many more who demonstrated in other capital cities around the world - have raised a pertinent question which has so far received only muted attention. What had driven the hijackers to die for their cause?
These were highly educated people who had not commandeered the aircraft and crashed them in a fit, but had put themselves through a long process of preparation to accomplish their feat.
Suicide attacks have a long history in the Middle East, and many Arabs who sacrificed their lives this way are revered as martyrs by their people. Until the Western world tries to understand the root cause of such deep-seated hatred, and does something about it, the supply of terrorists, or martyrs, will never end.