Q&A;: What is the relationship between IHL and terrorism?

IHL, the legal framework that applies to international armed conflict, non-international armed conflict, and situations of occupation, mentions terrorism but does not define it. To date there is no universally accepted single definition of terrorism.

Fundamental to IHL is the principle of distinction, which requires all parties to a conflict to distinguish at all times between civilian objects and military objectives and between civilians and combatants/ belligerents. An additional prohibition found in IHL is that which prohibits a party from making individual civilians or the civilian population writ large the object of attack. “Acts or threats of violence the primary purpose of which is to spread terror among the civilian population are prohibited” under Additional Protocol I (Art. 51) and Additional Protocol II (Art. 13). This is not a prohibition of any attack that provokes fear in the civilian population (as most certainly do), but rather it clearly prohibits attacks the central purpose of which are to frighten and intimidate civilians (i.e. shelling civilian areas). Furthermore, under Additional Protocol II, Art. 4, which provides for fundamental guarantees, “acts of terrorism” are prohibited, and under Geneva Convention IV, Art. 33 “collective penalties and all measures [...] of terrorism are prohibited.”

Thus, notwithstanding the absence of an explicit definition, IHL prohibits acts of terror – in addition to the clear obligation on the part of all belligerents to act in accordance with the principle of distinction (which is only one of a number of other principles and rules regulating the conduct of hostilities).

About the author
The author is an attorney in private practice in the United States focusing on international law and counterterrorism.