Understanding the diffusion of military capabilities is a central issue in international relations. Despite this, only a few works attempt to explain this phenomenon, focusing on threats. This article explains why threats alone cannot account for cybercapacity-development diffusion and introduces a more consistent explanation: the role of alliances. Allies with cybercapacity help partner-countries without cybercapacity start developing their own capacity to increase the alliance’s overall security by reducing mutual vulnerabilities in cyberspace. Partner-countries that lack cybercapacity are eager to accept this option because it is more favorable than developing cybercapacity on their own. Partner-countries may also start investing in cybersecurity to reduce the likelihood of being abandoned in other, conventional, domains. My new cross-sectional time-series dataset on indicators of a state’s cybercapacity-development initiation for 2000–18 provides robust empirical support for this argument and offers important implications for scholarship on arms, allies, and diffusion.

中文翻译：

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盟友和国家军事网络能力的扩散

了解军事能力的扩散是国际关系中的一个核心问题。尽管如此，只有少数著作试图解释这一现象，并重点关注威胁。本文解释了为什么威胁本身无法解释网络能力发展的扩散，并引入了一个更一致的解释：联盟的作用。拥有网络能力的盟友可以帮助没有网络能力的伙伴国家开始发展自己的能力，通过减少网络空间中的相互脆弱性来提高联盟的整体安全。缺乏网络能力的伙伴国家渴望接受这一选择，因为这比自己发展网络能力更有利。伙伴国家也可能开始投资网络安全，以减少在其他传统领域被抛弃的可能性。我关于 2000-18 年国家网络能力发展启动指标的新横截面时间序列数据集为这一论点提供了强有力的实证支持，并为有关武器、盟友和扩散的学术研究提供了重要的启示。