This paper proposes to think counterfactually about international law: How could it have been otherwise? Asking that question has the benefit of, first, exposing contingencies in international law’s development that are otherwise glossed over in the rush towards making sense of what happened. Second, counterfactual thinking supports the understanding of what actually happened in a context-sensitive fashion. Third, it forms part of comparative moral assessments and exposes blind spots. Counterfactual thinking may thus contribute to the freedom from necessity, from grand theory, and from reality. The paper draws the contours of what writing counterfactual (hi)stories of international law is about, discusses its merits as well as drawbacks, offers guidance on how to do it, and then focuses on two probing examples: What if the International Trade Organization had been established around 1949? What if garment workers were seals and the European Commission prohibited the importation of certain textiles?