Defining terrorism has always been a difficult exercise. Past work on a general definition of terrorism has often been controversial, and no consensual definition has emerged at the international level. Without a definition, it is difficult to decide what constitutes a terrorist act, and it becomes problematic to formulate or enforce international agreements against terrorism.

Defining terrorism became even more difficult following the terrorist attacks of 9/11 and adoption by the Bush administration of the phrase 'war on terrorism' which many countries consider inaccurate and too broad. Middle East and African countries in particular, felt that terrorism against tyranny was acceptable and did not want to condemn national liberation movements as act of terrorism.

The challenge of reaching consensus on a definition of terrorism exists not only at the international level, but also at the national level. For example, U.S. government departments and agencies provide a variety of definitions. President Bush's National Security Strategy of the United States of America, the Federal Bureau of Investigation, the Department of Defense, the U.S. Criminal Code, as modified by the 2001 PATRIOT Act, and the Department of State, rely on their own definitions of terrorism, which are often quite different from one another.

The inability to define terrorism has prevented the emergence of a coordinated, effective counter-terrorism strategy among nations of the international community. The failure of the United Nations in this regard is a testament to the inherent difficulties associated with defining this phenomenon. Divergent viewpoints about what constitute terrorism and whether a definition is necessary or desirable has given terrorist organizations an advantage and placed countries in a vulnerable position. Without a coordinated international counter-terrorism effort, responses to terrorist acts will continue to be slow and reactive, while preventive measure will be minimal.

After 9/11, the United Nations Security Council (UNSC) adopted general legislative measures against terrorism-with serious legal consequences-without defining it. The UNSC has instead encouraged states to unilaterally define terrorism in national law, permitting wide and divergent definitions. It failed to define terrorism until late 2004, despite using it as an operative legal concept with serious consequences for individuals and entities. The Council's 2004 definition raises other problems, since it is non-binding (allowing states to preserve unilateral definitions) and potentially conflicts with multilateral treaty negotiations on terrorism.

The UNSC, however, adopted several resolutions following 9/11. By resolution 1373, UNSC imposed sweeping legal obligations on all 191 UN member states. It requires every country to freeze the financial assets of terrorists and their supporters, deny them travel or safe haven, prevent terrorist recruitment and weapons supply, and cooperate with other countries in information sharing and criminal prosecution. Further, by resolution 1373, the UNSC mobilized states for a campaign of non-military cooperative law enforcement measures to combat global terrorism. Furthermore, the resolution also led to the establishment of the Counter-Terrorism Committee. In April 2004, the UNSC further strengthened the UN counter-terrorism programme by adopting Resolution 1540. The new resolution prohibited states from providing support to non-state actors that attempt to acquire nuclear, chemical, and biological weapons. In October 2004, it approved resolution 1566. Though these measures were useful, many countries have expressed the view that a convention with an unsatisfactory and non-binding definition of terrorism would not be worthwhile.

As far as the UN General Assembly is concerned, there have been many attempts over the years to arrive at a consensual definition, but such efforts have failed so far. Recently, it adopted a resolution on a strategy to counter international terrorism on 8 September 2006. Despite the resolution's consensual adoption, a number of speakers from the Middle East and African countries regretted that it had not included a definition of terrorism or any specific reference to 'state terrorism.' They argued that the strategy should have distinguished between 'terrorism' and 'the legitimate rights of people' to determine their own future.

To sum up, it can be argued that defining terrorism is not merely a theoretical issue but an operational concern. Terrorism is no longer a local problem of specific countries but an issue involving a number of international aspects. Since terrorism is a global phenomenon, responses to terrorism must also be global. Developing an effective international strategy requires agreement on what we are dealing with. A definition of terrorism is needed and the more objective the definition, the easier it will be to reach international agreement. The sooner countries arrive at a consensual definition of terrorism, the better it would be for the world to fight it.