It is only in the last 2 decades that terrorism has developed a significant international dimension. This has occurred because a spectacular act of violence which involves more than one country is the surest way to acquire widespread publicity. In addition, terrorists have used international violence to force more and more countries to take a vested interest in the outcome of their struggle. Finally, in some cases such as that of the Palestinians, there is no other battlefield available. Further, the fact that some States actively support, if not promote, terrorist activities makes the international regulation of the problem extremely difficult. Governments may also offer passive support or allow the terrorists to use their territories as bases of operations, the Jordanian Government did in its relationship with the Palestinian fedayeen. Other governments may strengthen the terrorist cause by capitulation. Also, trends within the terrorist movement itself, such as increasing terrorist solidarity and growing sophistication in weaponry may block the successful implementation of countermeasures. Governments need to adopt effective police and security measures to combat terrorism while preserving the civil liberties of the majority of its citizens. Eight footnotes are given.