The work approaches the concept of preventive self-defense against globally operating terrorist groups and "rogue states" as outlined in the 2002 National Security Strategy of the USA, set against the historical backdrop of preventive war. The impetus for this is provided by the document known as the Bush Doctrine itself, which places this broadly understood right to self-defense within a tradition linked to international law from past centuries. Therefore, the first question directed towards the past in the investigation is whether there is a continuity in the legal assessment of preventive warfare that can be traced from the present back to the beginnings of modern international legal science. The starting point is the work of the Dutchman Hugo Grotius, whose 1625 publication "De iure belli ac pacis libri tres" is regarded as the most prominent expression of early modern international law. Following this answer, a second question, now directed towards the future, arises: Does the right to preventive self-defense fit into this continuity, or does it break with it?.