The savage Leela, upon the destruction of an alien ship come to destroy the earth, asked the [fourth] Doctor, "Isn't it right to rejoice at the death of an enemy?" The Doctor, still patient with his companion, as with a child who has yet every important lesson to learn, answered, "we will discuss morality later."
There are two ways that America and the formerly Christian west can lose the war on terror. One way to lose is to give in to the fear and yield power to the enemy. The other way to lose is let that enemy change us. A certain feeling of relief is understandable, as is closure for family and friends of people killed by the evil plots of Bin Laden. But, parties and celebrations to rejoice at the death of an enemy is a spectacle that is wholly new to the modern western world. It is unprecedented, because those who lived in a more Christian culture knew that such behavior has no place in the customs of civilized people.