AFTER EXAMINING THESE USES, THE CONCEPT OF PREVENTIVE DETENTION IS CRITICALLY ANALYZED. IT IS DEMONSTRATED THAT A FAIR AND EFFECTIVE PREVENTIVE DETENTION SYSTEM REQUIRES AN OBJECTIVE DEFINITION OF DANGEROUSNESS AND A RELIABLE METHOD OF DETERMINING IT. NEITHER OF THESE REQUIREMENTS HAS BEEN DEVELOPED SATISFACTORILY, AND, CONSEQUENTLY, PREVENTIVE DETENTION CAN BE EASILY ABUSED BY A STATE POWER. BECAUSE OF THIS POTENTIAL FOR ABUSE, THIS ARTICLE CONCLUDES THAT ANY USE OF PREVENTIVE DETENTION MUST BE SUBJECTED TO RIGOROUS SCRUTINY AND EFFECTIVE SAFEGUARDS. (AUTHOR ABSTRACT)