He is required to be cool in a crisis, show courage in the face of danger, lead by example, and make the right decision when the stakes are life and death.
Infantry lieutenants and second lieutenants were the most common officers encountered by enlisted men on the Western Front as they commanded the smallest practical sub-unit of a battalion: the platoon.
Unlike officers of more senior rank, the infantry lieutenant shares the dangers and the hardships of his men. He inspects their feet to guard against trench foot and he censors their letters home. He is one of them, yet the decisions he makes can affect whether they live or die.