Nuestra NEBRIJA 35 - octubre 2020

36 Nebrija Research Carlos Espaliú Berdud Lead researcher of the Security, Risk and Conflict Management research group (SEGERICO) The rules and norms that regulate the use of force have always constituted the hard core of international law. In fact, many consider -maybe wrongly- that what is also called Law of Nations was born from the codifying work carried out in 1625 by Hugo de Grotius in his immortal work De Iure bellis ad pacis (On The Law of War and Peace). In that book, Grotius collected, commented on and developed the rules that regulated resorting to warfare, conducting battles, neutrality in a conflict, peace treaties... That is, international law was originally, for the most part, the regulation of war and the aspects that revolve around it. Of course, over centuries, international lawhas grown enormously and today has many branches, although the main body continues to be the set of rules that regulate the use of force. On the horizon of war, for millennia, the right of States to use force was never questioned until the power of weapons and their destructive ability reached such a level that any modern battle was liable to cause tens of thousands of deaths. Then, in the second half of the 19th century, attempts were made to limit the right to resort The rules that govern the legitimate defense of States in International Law are becoming obsolete because, in recent years, the nature of the actors that threaten the security of countries, as well as the nature of the attacks themselves, have changed. Terrorist attacks and self-defense in international law: evolution or revolution? T he W orld W ars had to happen for humanity to be convinced that war had to be prohibited , or its survival would be at stake