Why Isn’t There More Soft Law? A Response to Raustiala

In How International Law Works I grapple with the question of how states make the trade-off among the various features of agreements, including hard and soft law. I am not sure I agree that Kal’s empirical puzzle actually exists, but let’s assume it does and see why that might be so. A very similar question is discussed in the book – why are dispute resolution procedures almost never used in soft law agreements? The argument in the book (pp. 157-161) is very close to what follows.

One possible explanation for why we do not see many large, high-profile multilateral agreements can be seen by imagining a move from a soft-law agreement with few clear substantive obligations (e.g., the Rio Declaration) to an agreement that involves a greater level of commitment. One can imagine doing this in two ways (in fact, there are more than two, but let’s keep it simple). First, the states could stick with a soft law form, but provide more specific obligations. States would not be legally bound, but there would be a clear statement of what is expected of them. A failure to live up to the agreement would have some costs, though presumably less than the costs of violating the same agreement if it were a treaty. Second, states could leave the language unchanged but turn the agreement into a treaty. This would leave obligations somewhat vague and therefore give states some flexibility in how they behave while still claiming compliance.

Kal’s empirical claim raises the question of why we don’t see more of the first category (soft law with clear terms) and less of the second (treaties with vague terms), at least in some high-profile contexts. Why was the Vienna Convention for the Protection of the Ozone Layer a vague treaty rather than a soft law instrument? A partial answer comes from thinking about what sort of state preferences would yield that result. We expect this outcome if we assume that states prefer to increase their level of commitment by increasing the formality of the promise rather than its precision. This suggests that the choice of hard law offers a better cost-benefit trade-off to states than does the choice of more exact language. This, of course, begs the question of why they have that preference, and I do not have a satisfying response. The good news is that there is a lesson to be learned here. Perhaps Kal’s empirical puzzle is not such a puzzle at all, but instead tells us something we did not previously know about state preferences and the trade-offs states face.