Countries using Proportional Representation not only have more representative legislatures, but also tend to have significantly less involvement in armed conflict.
Lower Likelihood of Armed Conflict
Leblang and Chan found that the electoral system is the most important institutional predictor of a democracy’s involvement in war. Established democracies with systems of PR tend to have significantly less involvement in armed conflict. They found, “a proportionate- representation system turns out to be consistently significant in dampening war involvement in all three meanings we have operationalized in this context.”
The three meanings of “war” referred to are: 1) likelihood of being the first to enter into war, 2) likelihood of joining a multinational coalition in an ongoing war, and 3) likelihood of remaining in a war it is already involved in. Separately, Orellana found that the predicted level of military expenditure for countries with majoritarian systems was more than twice as high as for countries with fully proportional systems.
Leblang and Chan comment: “What is it about the nature of a PR system that discourages foreign belligerence?... Instead of supposing that only competitive politics can restrain war involvement, an informal culture and a traditional practise of consensual politics may serve as an equally and perhaps even more effective barrier to such involvement ... European countries with a PR system tend to have parliamentary majorities based on an oversized coalition with participation from several parties. Even where there is one dominant party, they tend to offer a more encompassing coalition with institutionalized representation of various sectoral interests. Their political process acknowledges multiple veto groups and promotes regular consultation to develop consensual policy.”
In short, when the people are fairly represented in Parliament, more of those groups who may object to any potential war have access to the political power that is necessary to prevent it. In a proportional democracy, war - and other major decisions - generally requires the consent of the majority.
Leblang, D., & Chan, S. (2003). “Explaining Wars Fought By Established Democracies: Do Institutional Constraints Matter?” Political Research Quarterly 56-24: 385–400.
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