O'Brien is in the infantry, and the main thing the infantrymen do in Vietnam is walk. They walk through the jungle on patrol, and they walk the perimeter on guard duty. Walking represents the soldiers' endurance; it is their way of getting on with it, acceding to the business of war. It also represents the endless nature of the soldiers' activity in Vietnam; it is not a war of territory, in which they hunker down and hold an area of land, and it is not a battle for hearts and minds, O'Brien believes. Therefore, there is nothing else for the soldiers to but walk:"If land is not won and hearts are at best left indifferent; if the only obvious criterion of military success is body count and the enemy absorbs losses as he has […] if any of this is truth, a soldier can only do his walking" (127). Walking is also a motif in some of O'Brien's books, particularly the novel Going After Cacciato, in which the titular soldier Cacciato goes AWOL and walks from Vietnam to France. But walking also represents the soldiers' vulnerability to mines and booby traps. Therefore, the soldier does a “funny step” with his walking, O'Brien writes in If I Die in a Combat Zone.