This chapter is a comment on the capacity of international law to address complex problems such as climate change, as a complement and response to Jutta Brunnée’s preceding chapter. The comment first questions whether complexity is in fact a special case or rather an all-pervading characteristic of international relations, and by extension, of international law. Second, the comment questions—notwithstanding the current angst that internationalist lawyers feel and express due to what seems like a tidal-scale assault on international law—whether the international rule-of-law management of complexity is a particularly contemporary issue, or just another iteration of recurrent, resurgent, occasionally even refreshing, frictions that characterize international law. Third, the comment asks whether the challenges of complexity maintain a special relationship with international law, or whether these are substantially the same as the interactions of these issues with domestic legal systems.