BECAUSE SELF-DEFENSE IS THE ONLY LEGITIMATE USE OF FORCE UNDER THE CHARTER OF THE UNITED NATIONS, AND BECAUSE 'COLLECTIVE SECURITY' GUARANTEES FAIL TO PROTECT VITAL INTERESTS, STATES HAVE ENDEAVORED TO BROADEN THE CONCEPT OF 'AGGRESSION' TO INCLUDE INDIRECT COERCION. SUCH A SEMANTIC CHANGE WOULD JUSTIFY ACTION AGAINST COERCION FROM IRREGULAR FORCES. HOWEVER, RETALIATION AGAINST GUERRILLAS WOULD NOT BE SELF-DEFENSE, EVEN IF THE ACTION WAS JUSTIFIABLE. WHERE TERRITORIAL INTEGRITY AND INDEPENDENCE ARE NOT IMMEDIATELY AND SEVERELY AFFECTED, NO GROUNDS EXIST FOR SELF-DEFENSE; GUERRILLA VIOLENCE SELDOM PRESENTS AN IMMEDIATE THREAT TO VITAL INTERESTS. YET, IF STATES SERVING AS STAGING AREAS FOR GUERRILLAS FAIL IN THEIR OBLIGATION TO POLICE IRREGULAR OPERATIONS AND REFUSE TO ASSIST IN ENDING THE OPERATIONS, THEN TARGET STATES MAY LEGITIMATELY CONFRONT VIOLENCE WITH VIOLENCE. IN THE ABSENCE OF EFFECTIVE COMMUNITY ACTION TO ENCOURAGE RESTRAINT, SELF-HELP REMAINS THE ONLY ALTERNATIVE. THE PROPER DEGREE OF RETALIATION DEPENDS UPON THE ESTIMATED CONSEQUENCES OF FAILING TO ACT AND RESORTING TO FORCE WITH MODERN WEAPONS. ALTHOUGH UNSCRUPULOUS STATES COULD TAKE ADVANTAGE OF A NATION WHICH HESITATES TO ACT, OVERREACTION SEEMS CONTRARY TO THE INTERESTS OF ORDER. A DISPROPORTIONATE DEGREE OF FORCE OR AN INAPPROPRIATENESS OF OBJECTIVES COULD RESULT IN THE INTERNATIONAL CONDEMNATION OF THE RETALIATING STATE. NEVERTHELESS, IN EVALUATING CLAIMS FOR ACTION AGAINST GUERRILLAS, THE USE OF FORCE MAY BE JUSTIFIED BY AN 'ACCUMULATION OF EVENTS' COMMITTED BY THE GUERRILLAS. ITS USE SHOULD BE DIRECTED AGAINST MILITARY AND PARAMILITARY TARGETS ONLY AFTER PEACEFUL RESOLUTION EFFORTS ARE EXHAUSTED. FOOTNOTES ARE PROVIDED. (TWK)