Post-modern theory goes further. There are only stories and they are only about themselves and their tellers' preoccupations. Stories about international legal theory, like most legal and political talk in the modern world, relate to a single, controlling argument. Modernity is but a running argument over the practical implications of liberal ideas. Where modern theory finds rules, post-modern theory puts texts.
Social process is discourse by various means.
Yet texts contain rules, and rules contain texts. Discourse depends on the rules that discourse produces. Rules and the choices they afford connect arguments over liberal premises to people's practical concerns. Post-modern scholars err in equating what scholars do as scholars with what everyone does all of the time. People can and do argue.