The Kansas v. Hendricks (1997) decision, in which the Supreme Court authorized post-sentence civil commitment for certain sex offenders, appeared to be constitutionally legitimized by limiting the class of offenders eligible for this special form of civil commitment to those who are "unable to control" their dangerousness. Nowhere in the available record, however, did the Court elucidate what they meant by this notion of volitional impairment. This study sought to examine factors that legal professionals (n=43), psychologists (n=40), and mock jurors (n=76) deem most relevant to a determination of sex offender volitional impairment. Participants, who were randomly assigned to a sexual predator commitment or an insanity hearing context, read a series of 16 vignettes that described a pedophilic offender and included combinations of variables hypothesized to be related to judgments of volitional impairment. Results suggested that participants, who as a group made remarkably high estimates of likelihood of future sexual violence, considered verbalization of control, history of sexual violence, and the context of the hearing as highly relevant to determinations of volitional impairment. Implications for policy and practice are explored.