Defense occupies a richly contested position across the depth-psychology corpus, spanning at least three distinct registers that rarely speak directly to one another yet share a common concern: the organism’s—or psyche’s—effort to maintain integrity against threat. In the somatic-trauma tradition represented by Ogden, Porges, and Nijenhuis, defense is primarily an instinctual, phylogenetically conserved repertoire of animal responses—fight, flight, freeze, shutdown, and cry for help—whose chronic activation underlies dissociative and post-traumatic symptomatology. Here the body is the locus of defensive action, and the therapeutic task is to complete or metabolize responses that were interrupted. In the structural-dissociation framework of van der Hart, defense shades into resistance: the patient’s defensive actions protect against integrating feared experience, and the clinician must work with rather than against these tendencies. Patricia Berry, writing from within archetypal psychology, radically reframes the Freudian conception: the defense is not merely an obstruction to unconscious content but its mimetic double—it expresses and simultaneously conceals what it would ward off, and therapeutic movement proceeds by deepening the likeness the defense has already formed to the avoided content. This Jungian inflection opens toward a teleological reading in which defenses carry the very material they ostensibly suppress. Mathieu adds a further dimension by identifying spiritual bypass as a defense mechanism specific to recovery contexts. Taken together, these positions reveal that ‘defense’ in depth psychology names not one thing but a spectrum: from neurophysiological reflex to archetypal mimesis.