Why did Lieutenant Jimmy Cross feel guilty about Ted Lavender's death?

Tim O’Brien’s novel The Things They Carried is the story of an army unit in the Vietnamese War. O’Brien uses the characters’ experiences to demonstrate the effects of war on the young soldiers.

Early in the story, O’Brien establishes a major internal conflict that First Lieutenant Jimmy Cross must deal with: the death of a soldier named Ted Lavender. To understand how Lavender’s death affects Cross, we have to first understand his character.

Cross is in love with a woman named Martha back in the states. One of the effects of the war is to heighten Cross’ feelings of love for her, even though she seems to be generally indifferent to him. His thoughts continually turn away from war to more pleasant thoughts of her.

One day, as the unit is working on clearing tunnels, Cross begins to daydream about Martha:

. . . he was not there. He was buried with Martha under the white sand at the Jersey shore.

This line shows us that Cross is not fully engaged with the unit’s activities. Moments later Lavender is shot and killed by an unseen enemy sniper. Cross’ reaction is to feel an overwhelming sense of guilt:

He felt shame. He hated himself. He had loved Martha more than his men, and as a consequence Lavender was now dead, and this was something he would have to carry like a stone in his stomach for the rest of the war.

As so often happens in real life, Cross’ guilt is irrational but devastating. It was not really his fault that Lavender was killed—if anything it was Lavender’s own fault, but Cross cannot stop himself from feeling responsible. He had been off in his own world, thinking about Martha, who probably cared less about him that his own men did, and Lavender died.

Cross probably would have felt some guilt no matter what the circumstances of Lavender’s death were, but the fact that he was daydreaming at the time makes it very easy to blame himself.