The motive for war is to devote one's life to the maintenance of an omnipotent object; demonstrating one's devotion by the willingness to give one's life; offer one's blood upon the altar of the nation, fuse with the immortal object.  Why did the soldier in the First World War yell "Long live France" when he was about to attack the enemy trench?

 Because a nation is the phantasy of an immortal object. The soldier's death sustains the viability of this dream, giving rise to the "nightmare of history."