Lieutenant Jimmy Cross was deeply in love with the image of a girl back home, Martha. All through his tour, he thought of Martha. He read her letters and carried them with him while on patrol. As is common for soldiers far from home, and especially those serving in combat, Lieutenant Cross became almost obsessed with those images, with what he believed Martha was doing and, more importantly, with whom she was doing it. The story of the pebble Martha sent Lieutenant Cross in the mail, for example, both touched and terrified him. The pebble was a thoughtful gesture, but he became obsessed with the thought of who Martha was with when she found it:
"Martha was a poet, with the poets sensibilities, and her feet would be brown and bare, the toenails unpainted, the eyes chilly and somber like the ocean in March, and though it was painful, he wondered who had been with her that afternoon...It was phantom jealousy, he knew, but he couldn't help himself. He loved her so much."
So immersed in thoughts of Martha was Lieutenant Cross, that his mind wandered when he should have been solely focused on the task at hand. As a platoon leader, he was responsible for the lives of 30 men under his command. Suddenly, Ted Lavender was dead, and Cross blames himself for losing focus. O'Brien describes the scene as follows:
"He [Lieutenant Cross] 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."
In "The Things They Carried," Martha represented the kind of psychological baggage that can get men killed. She was the psychological baggage carried by Lieutenant Cross, a distraction that interfered with his primary (unofficial) job of keeping his men alive.