This group of 17 and the 250 to 400 suspects placed at any one time on the surveillance list of the Secret Service contrast sharply with the more than 26,000 people who have been investigated as potential threats to the president or other prominent political figures. However, both the actuarial approach and the clinical approach commonly used in dangerousness predictions have significant limitations. The analysis of dispositional and contextual factors related to the 17 individuals in the author's research suggests a typology based on seven characteristics: emotional distortion, cognitive distortion, hallucinations, delusions, reality contact, social relations, and primary motive. The typology includes four groups: rational political extremists, people with either of two types of mental and emotional disturbance, and the insane. The situational indicators included detection indicators like suspicious behavior in proximity to the political figure, engagement indicators like stalking behavior and interest in the intended victim, and disengagement indicators like occupational instability and family estrangement. These and other indicators are particularly relevant to identifying the danger posed by the most common suspects, who are those with mental and emotional disturbances. Tables and reference notes.