New study reveals why unanimity rule causes conflict and delays in international agreements

In a recently published study in the American Economic Journal: Microeconomics, Finnish economist Topi Miettinen (Hanken School of Economics, Helsinki) and German economist Christoph Vanberg (University of Heidelberg) develop a theoretical explanation for why rational behavior might produce conflict and delay in the context of unanimity rule.
The study models a multilateral bargaining process in which participants can strategically pre-commit to oppose agreements which do not concede certain demands. For example, politicians might publicly threaten to veto an agreement unless certain concessions are made. Once such announcements are made, accepting a less favorable outcome can be politically costly. Thus, such announcements can be an effective means of tying one’s hands in subsequent negotiations.
As an example of such tactics, the authors point to Turkey’s tough public posturing prior to NATO’s vote on the entry of Finland and Sweden. In response, Finland and Sweden conceded to lift arms embargos and adopt counter-terrorism policies as demanded by Turkey, and the United States authorised the sale of F-16 fighter jets.
“Thus, Turkey successfully used the requirement of unanimity to extract concessions from its bargaining partners. This tactic was associated with potentially costly delay and indeed a risk that the agreement might fail. Similar tactics have been employed in the EU context, for example when Hungary has blocked EU sanctions against Russia and delayed aid to Ukraine, attempting to pressure the EU on unrelated rule-of-law disputes and funding issues”, says Professor Topi Miettinen.
The theoretical model predicts that such posturing and associated delays are common when unanimity rule is applied. It also suggests that these problems are more pronounced if the number of negotiating parties is large and if they meet infrequently.
“Most importantly, it suggests that conflict and delay will be significantly reduced if any qualified majority rule (QMR), short of unanimity, is adopted. That is, even an all-but-one rule completely eliminates the incentive for strategic posturing”, Professor Christoph Vanberg explains.
This insight is especially timely. In recent years, high-ranking EU officials have increasingly voiced frustration with the unanimity requirement. European Commission President Ursula von der Leyen has stated: “In foreign affairs, we really have to move to qualified majority voting… the speed at which things happen … is too high to constantly, or too often, not be heard and seen, because of the blocking of one.” (Politico June 20th 2022).
The study lends support to proposals to replace unanimity rule with a QMR. In the EU context, the proposal to expand the use of QMR as currently defined has been met with resistance by small member states who fear that they may be outvoted. With this in mind, the authors emphasise that a much more demanding QMR short of unanimity may significantly improve the efficiency of decision making while lessening the risk to be outvoted.