Historians of international law are beginning to perceive the extraordinary significance of the 1990s for the development of the field. That it was a decade of unprecedented institutional growth has been long evident – growth of human rights law and environmental law, the establishment of the World Trade Organization, the newly found consensus among the members of the UN Security Council. And to cap it all, the rallying of like-minded actors and institutions under the banner of the ‘international community’ behind the effort to eradicate war crimes and crimes against humanity. The project to draft a code of international crimes and to provide for the criminal responsibility of high military and political leaders had been under way in the UN since the end of the Second World War. Finally in the 1990s, the Statute of an International Criminal Court was adopted (1998) and proceedings began in many domestic courts against foreign leaders accused of grave violations during their time in office. From the perspective of activities and expectations of the long years of the Cold War, these developments – that belong together in a kind of liberal revolution – were indeed remarkable. But equally astonishing has been the backlash in the second decade of the 2000s against many, if not most, of these developments. The illegal war in Iraq, with all its repercussions in the West and, of course, in the Middle East, the failure of the Arab Spring, Russian occupation of Crimea, the so-called ‘refugee crisis’ and the economic downturn since 2008 either crushed the liberal consensus, or at least demonstrated the extreme fragility of what had been achieved. Historians’ interest in the 1990s is not, therefore, just about what made 1990s seem so ‘progressive’ in the eyes of most, but how such a sense of progress was so easily dispelled. Of course, to some extent, the backlash was caused by forces that had never joined the consensus. But there must have been something in the institutional and legal projects themselves that contributed to the present malaise and stagnation. What did we fail to see then? There is a great need to place the period 1989–2016 under close analysis, in part so that we who are contemporaries of the events would understand, but also for those who in the future will try to advance the objectives of peace and justice through international institutions.