How do unbalanced nuclear alliances provide extended nuclear deterrence (END) to their members? Why have nuclear alliances chosen certain types of END strategy and not others? Existing accounts regard END as a function of the inter-alliance balance of power, regime type, or institutional design. END strategies inspired by theories focused on regime type and institutional design have not yet materialised, while the inter-alliance balance of power does not suffice to explain the choice of END strategy. To elucidate variations in END strategy, this article puts forward an argument centred on the intra-alliance balance of power. Drawing on the history of the US-led and the Soviet-led alliances during the Cold War, namely North Atlantic Treaty Organization and the Warsaw Pact, it shows how the two superpowers changed their approach to defending their allies with nuclear weapons according to quantitative and qualitative shifts in the distribution of power within the alliance.

中文翻译：

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力量平衡：核联盟和扩展威慑的逻辑

不平衡的核联盟如何为其成员提供扩展的核威慑（END）？为什么核联盟选择某些类型的 END 战略而不选择其他类型？现有账户将 END 视为联盟间权力平衡、政权类型或制度设计的函数。受政权类型和制度设计理论启发的 END 战略尚未实现，而联盟间的权力平衡不足以解释 END 战略的选择。为了阐明 END 策略的变化，本文提出了一个围绕联盟内部权力平衡的论点。借鉴冷战期间美国领导和苏联领导的联盟，即北大西洋公约组织和华沙条约组织的历史，