How can the use of force by states be constrained under international law?  Under what circumstances has the use of force by states been deemed "legitimate"?  How are rules about the legitimate use of force changing?  These questions are examined in depth, along with the relevant instruments of international law.  The chapter details the various ways that "force" and "aggression" have been defined and used.  It treats all the major forms of force or coercion, including full-scale military operations, economic sanctions and reprisals, proxy and clandestine forces, small-scale conflicts.  It then traces growing prohibitions on the use of force from the League, the UN, the ICJ, and other sources.  Finally, the Laws of Armed Conflict are highlighted as are the Geneva Conventions and instruments limiting munitions and conflict on the land, air, and sea.  The use of drones and autonomous weapons systems, guided by AI, are highlighted as a growing area of concern for international law.

The chapter examines the recent changes in the nature of modern warfare. It argues that most recent military conflicts take the form of “low-intensity conflict,” “gray-zone competition,” “asymmetric warfare,” “fourth-generation warfare,” and “irregular warfare.” Given the huge military spending gap between Iran and its regional and global adversaries, Iranian leaders have articulated and adopted an asymmetric warfare doctrine since the 1979 revolution.