In the grand debates of international law, the jus ad bellum is often proclaimed dead, and just as often praised as the cornerstone of the contemporary legal order. Both perspectives tend to ignore that the jus ad bellum is not static, but a body of law that states adjust over time. In an important contribution, Monica Hakimi proposes to look at one particular aspect of such adjustment, a concept she frames as informal regulation through Security Council action. This essay engages with Hakimi's approach. It inquires whether this approach is as informal as Hakimi suggests, and asks whether informal regulation - rather than constituting a new category of state activities to study - is not already part of conventional approaches to the jus ad bellum. Proceeding from Hakimi's analysis, the comment assesses whether there is room for informal regulation beyond the Security Council.