In today's international scenario peace is increasingly entangled with violence. From the civil war in Yugoslavia to the Nato intervention in Kosovo, from the 9/11 attack to the wars in Afghanistan and Iraq, violence has appeared to be a constant presence in international relations. But its real specificity concerns violence's ability to evade the rules of the past, according to which only certain actors (states) could resort to force, that only certain individuals (soldiers) could be subject to violence, that only certain procedures (declarations of war and peace treaties) could usher in periods of war or peace. A deep crisis of rules, that had already been initiated by the other armed conflicts of the 20th century, was definitively established after the end of the cold war, thus reflecting a more general crisis of principles and basic rules underlying international relations.

Alessandro Colombo teaches International Relations at the University of Milan.