In 1992, Alexander Wendt shook up the world of International Relations Theory by publishing an article titled 'Anarchy is what States make of it: the social construction of power politics'.
Wendt argues that anarchy can be a structural fact about the world that
states inhabit, but that it is up to politicians (and IR scholars) to
decide how to deal with that anarchy. Since then, Wendt’s social
constructivist approach to International Relations has gained a lot of
interest and one cannot talk about IR Theory without mentioning his
work.