Weighted Voting in the United Nations Security Council

Various observers have proposed weighted voting as part of an overhaul of the UN Security Council. This article employs game-theoretic methods to simulate the effects of weighting votes in the UN Security Council according to the ability of individual states, as well as on the ability of the Council to act. The authors first briefly review reform proposals. Drawing on recent proposals, they then calculate voting weights based on population, contributions to the UN, and a measure of sovereign equality. These component measures are assigned different weights in order to formulate three sets of weighted votes. After this, they define several measures of voting power that can be used to assess voting power in weighted voting systems. The measures used in this article assess the relative voting power of individual members as well as the probability the Council will engage in collective action to pass a resolution. Results of voting power simulations are then presented under both simple and qualified majority rules. The authors’ simulations indicate that under weighted voting the capacity of the Council to act is likely to increase under most conditions unless high qualified majorities are required. The simulations also demonstrate that the main problem identified with weighted voting—large deviations between voting weight and voting power—are not present in the weighted voting systems analyzed here.