Psychiatry’s limited conceptualization of volitional capacity becomes problematic when the concept is used in the legal arena to uphold the constitutionality of civil commitment for sexually violent predators. The author explores the concept of volitional capacity as it is applied in psychiatry and in its application to law. Two legal opinions that are critical for sexually violent predator case law, Kansas v. Hendricks and Kansas v. Crane, are examined to illuminate the problems inherent in applying vague psychiatric concepts to legal contexts. The psychiatric literature concerning volitional capacity and volitional impairment is reviewed; the author notes the limitations in the understanding of the concept within the field of psychiatry. The field of psychiatry lacks a valid or reliable method to infer a patient’s volitional capacity and no uniform clinical definition exists. The medical literature describes volitional capacity loosely as impulse control and compulsive behavior. The medical literature also alludes that elements of volition may be psychiatrically evaluated. The author concludes that while further study is needed to operationalize volitional capacity, the clinical concept does have promise for legal application. Three distinct clinical concepts are offered that may aid in operationally defining volitional capacity. References