Loneliness can be evaluated from a 4-concept viewpoint of territory, threat, trauma and trust (4 Ts). Territory refers to an area of ownership that is controlled on a daily basis and is fundamental to one's daily life. Lonely individuals often manage boundaries by gaining greater control over their physical environment by territorial behavior. They guard personal territory well as the only area where they can exert dominance and feel safe. Perceptions of social isolation or loneliness increase vigilance for threats, decrease trust, and heighten feelings of vulnerability. Clinical teams caring for the lonely must be especially attentive to a history of prior trauma. Clinicians who ask permission, who pay attention to nonverbal cues, distance, and speed as they enter the lonely person's space, and who respect boundaries may be more successful in gaining trust. Achieving trust diminishes the risk of physical harm, while allowing lonely persons the perceived control they need to permit health care interventions. Veterans are at higher risk for loneliness. Given their military training, they may be particularly attentive to boundaries, protecting the perimeter, watching for threats, and defending their space. In this article, we discuss the successful mental health treatment of a lonely male veteran in a Veterans Affairs Medical Center, by paying attention to the 4 Ts of loneliness. We used a 4-step approach of validation, mentalization, reality testing, and socialization to decrease the sense of threat as we sought acceptance to the patient's territory, followed by building trust and working on past trauma.