The paper's format is an objective analysis of the relevant law, much as a hypothetical international court would be expected to do. The underlying premise of the analysis is that all states are bound by common rules of international law, particularly by the principles of the United Nations Charter concerning the use of force. The discussion first reviews the legal definition of international terrorism and the pertinent obligations of states. This is followed by a summary of the various situations that have involved or may involve extraterritorial use of force by states against terrorism. This section refers to terrorist conduct that precipitates forcible responses, the categories of states that take such forcible action, and the relationship of the terrorist to the regime of the state in which they are located. The analysis then turns to the relevant principles of law on the use of force in another country. The first section considers the basic prohibition of force in the charter and customary law and its application to extraterritorial acts against terrorism. The second section examines self-defense as a permissible use of force. Particular attention is given to the requirement of armed attack as a condition for self- defense. The criteria of "necessity" and "proportionality" are also discussed. The third section considers whether or not forcible action against terrorists may be taken in circumstances where the conditions for self-defense do not apply. The paper notes in the concluding remarks that international law holds governments accountable both for failures to combat terrorism and for unrestrained and indiscriminate violence in retaliation. 60 notes