The rule of law has emerged both on the domestic and international levels as a promise of longstanding democracy, economic development and peace. On both levels, the rule of law is often associated with the longstanding character of institutions and the predictability of rules, meaning that ‘citizens are entitled to laws that are neither murky nor uncertain’. However, does this always mean in practice that the rule of law can only be concretized by laws and legal institutions that last forever? More specifically in the international context, can we guarantee the consolidation of the international rule of law through the coexistence of both permanent and temporary institutions and instruments? In this chapter, I analyse the meaning of the rule of law at the domestic and international levels and discuss its complex relationship with time. I argue that the past, present and future of the rule of law can be, in some cases, united by the use of temporary institutions such as international criminal tribunals or truth commissions, rules and measures. Temporariness can be essential to react swiftly to humanitarian crises, provide transitory justice, gradually concretize the rule of law in fragile democracies, and adapt legal orders to evolving economic and political circumstances.