Indeed, recent research has drawn attention to its inability to classify two recent agreements, namely the Paris agreement on climate change and the nuclear agreement with Iran. See Galbraith, Jean, From Treaties to International Commitments: The Changing Landscape of Foreign Relations Law, 84 u. Chi. L. Rev. 1675 (2017); Koh, Harold H., Triptych`s End: A Better Framework to Evaluate 21st Century International Lawmaking, 126 Yale L.J. F. 338 (2017). Since this article addresses the substantive difference between executive agreements and treaties concluded between 1982 and 2012 and does not deal with new forms of international agreements, there is little need to go beyond this traditional distinction.
The analysis sorts the chords according to their durability and assumes that x-quantil is exclusive, with x ∈ [0, 0,1]. For example, x = 0.03 estimates that the least sustainable agreements are single executive agreements. It then omits these agreements from the analysis, runs the preferred model (5) and collects the estimated coefficient for the contractual indicator and its standard error. Note that the assumption that the least durable agreements are exclusively executive agreements is extremely restrictive. In reality, it is much more likely that some single executive agreements will survive agreements between Congress and the executive. It is therefore to be expected that this approach will distort upwards the permanence of agreements concluded between Congress and the executive, making it more difficult to differentiate between the durability of contracts and executive agreements. While it can be demonstrated that even under these restrictive assumptions, contracts survive executive agreements, this provides particularly strong evidence of the greater sustainability of contracts. So far, the analysis has not distinguished between different types of executive agreements.. .