"In the theater of operations . . . the presence of the enemy, and his capacity to injure and kill, give the dominant emotional tone to the combat outfit. . . . The impersonal threat of injury from the enemy, affecting all alike, produces a high degree of cohesion so that personal attachments throughout the unit become intensified. Friendships are easily made by those who might never have been compatible at home, and are cemented under fire. Out of the mutually shared hardships and dangers are born an altruism and generosity that transcend ordinary individual selfish interests. So sweeping is this trend that the usual prejudices and divergences of background and outlook, which produce social distinction and dissension in civil life, have little meaning to the group in combat. Religious, racial, class, schooling or sectional differences lose their power to divide the men. What effect they have is rather to lend spice to a relationship which is now based principally on the need for mutual aid in the presence of enemy action. Such powerful forces as antisemitism, anticatholicism or differences between Northerners and Southerners are not likely to disturb interpersonal relationships in a combat crew. . . . Their association is not limited to working hours but includes their social activities. . . . The most vital relationship is not the purely social. It is the feeling that the men have for each other as members of combat teams and toward the leaders of those teams, that constitutes the essence of their relationship."