Terrorists must be some of the dumbest people on the planet to believe that terror can somehow further their cause. I wonder if in all of history there has ever been a case where terror resulted in something positive for the terrorists. End of day such acts only contribute to fuelling a vicious cycle of hatred. The fundamental problem is that humans have a capacity for evil! That might sound na�ve but is nevertheless true I think. There's an apothegm by Friedrich Nietzsche that goes like -

In individuals, insanity is rare; but in groups, parties, nations and epochs, it is the rule.

What this would mean is that acts of terror are perpetrated by terrorist groups (which tend to be insane by nature given that they are groups of people) that are led by sober, cold and essentially evil individuals who do the thinking and the planning; who cleverly exploit and misdirect restless energy in disgruntled youths; who know the exact words and notions that will appeal to them and even lend an illusion of grandeur to what they are doing.

I have always suspected that there exists a suicidal streak in humans as a species. This is perhaps just one of the ways in which that instinct has manifested itself.

http://www.iht.com/articles/2006/07/12/asia/web.0712india.php