Trauma Defense occupies a pivotal conceptual position across the depth-psychology corpus, bridging somatic, archetypal, and structural-dissociative frameworks. The literature reveals at least three distinct but overlapping treatments of the term. First, in the sensorimotor and body-oriented traditions represented by Ogden, Levine, and Nijenhuis, trauma defense designates an ensemble of phylogenetically conserved survival responses—freeze, flight, fight, feigned death, and social engagement—that become maladaptive when they persist beyond the originating threat, crystallizing as chronic sensorimotor habits. The crucial insight these authors share is that it is not the use of any particular defensive subsystem per se, but their inflexibility and overactivation, that constitutes pathology. Second, Kalsched, writing from a Jungian-archetypal perspective, theorizes trauma defense as an intrapsychic agency—the Protector/Persecutor—whose original purpose is the preservation of the personal spirit but whose very efficacy condemns the psyche to self-enclosure. This archetype-level formulation introduces a tragic irony absent from the somatic literature: the defense that saves also imprisons. Third, Nijenhuis and the structural-dissociation school situate trauma defense within an evolutionary hierarchy of predatory-threat substates, linking somatoform symptoms directly to discrete defensive phases. Across these traditions, the common and irreducible tension is between the biological necessity of defense in the moment of danger and its pathological persistence long after danger has passed.