EXAMPLES OF TERRORIST ACTIVITIES AND ORGANIZATIONS ARE CITED, WITH REFERENCE TO THE POLITICAL AND ORGANIZATIONAL SOPHISTICATION OF SOME TERRORISTS AND TO INTERNATIONAL TIES AMONG SOME TERRORIST GROUPS. ANTITERRORIST ACTIVITIES IN NORTHERN IRELAND, THE UNITED STATES, AND CANADA ARE DESCRIBED. IT IS POINTED OUT THAT A GOVERNMENT'S INITIAL RESPONSE TO AN URBAN TERRORIST THREAT IS CRITICAL IN THAT IT DEFINES THE ISSUES AT STAKE AND THE CHARACTER OF THE ANTITERRORIST CAMPAIGN. IT IS NOTED FURTHER THAT INHERENT IN ANY LIBERAL DEMOCRATIC STATE ARE FACTORS THAT IMPEDE THE COLLECTION OF INTELLIGENCE NEEDED BY DECISIONMAKERS TO SHAPE THE GOVERNMENTAL RESPONSE TO A TERRORIST THREAT IN ITS INCIPIENT STAGE. THE MAIN PROBLEM CONFRONTING POLICE IN A FREE SOCIETY ENGAGED IN ANTITERRORIST OPERATIONS IS THE DEVELOPMENT OF POLITICALLY ACCEPTABLE, LEGALLY PERMISSIBLE METHODS TO GAIN RELIABLE INFORMATION ABOUT TERRORISTS FOR IMMEDIATE TACTICAL USE. IT IS SUGGESTED THAT, IN A FREE SOCIETY, A TERRORIST ORGANIZATION IS CONTROLLED BEST BY THE SYSTEMATIC APPLICATION OF ROUTINE POLICE PATROL, INVESTIGATIVE, AND CRIME PREVENTION TECHNIQUES--PROVIDED THAT THE POLICE THEMSELVES ARE AWARE OF THEIR OWN ANTITERRORIST CAPABILITY. THE USE OF COVERT INTELLIENCE-GATHERING TACTICS, POLICE INTELLIGENCE SYSTEMS, AND NATIONAL INTELLIGENCE SERVICES AS ANTITERRORIST TOOLS IS DISCUSSED. THE NEED FOR A SPECIAL ANTITERRORIST ASSESSMENT AND RESPONSE GROUP IN THE UNITED STATES, CAPABLE OF GATHERING AND ANALYZING PUBLIC SECURITY INFORMATION FROM BOTH DOMESTIC AND FOREIGN SOURCES FOR REGULAR DISSEMINATION TO LAW ENFORCEMENT AGENCIES ON A 'NEED-TO-KNOW' BASIS, IS CITED. THE GROUP IS ENVISIONED AS A MECHANISM FOR CARRYING OUT ANTITERRORIST FUNCTIONS (INFORMATION GATHERING, INSTRUCTION, TECHNICAL ASSISTANCE) NOT PERFORMED BY THE CENTRAL INTELLIGENCE AGENCY OR FEDERAL BUREAU OF INVESTIGATION. (LKM)