Friendship is a concept often evoked on the international stage and which has a long history in international thought. Despite falling to the sidelines for some time, it is experiencing a resurgence of interest. This paper sets out the position of friendship in the international thought of Hugo Grotius. I show that Grotius develops a law of friendship ( amicitiae lex ) which he incorporates into his just war theory. I argue that he makes a conceptual distinction between allies ( socii ) and friends ( amici ). The distinction concerns the underlying legal bases upon which they are founded. I therefore argue that we can map this distinction onto another of Grotius’s distinctions, that between perfect and imperfect rights. This is an important point because an infringement of a perfect right can result in war, but an infringement of an imperfect right cannot. Additionally, I highlight the supererogatory character to which Grotius accords friendship. I conclude by arguing that friendship is an important concept in Grotius’s international thought. I also suggest that Grotius is an instructive figure not only for those engaged in friendship’s revival but also for those concerned with the identity and relations of states.
Charlie Bradley (Tue,) studied this question.