Abstract: Cyber deterrence is an important tool for maintaining network security. While the current theoretical studie shave argued that cyber deterrence is ineffective, the US government insists on emphasizing the importance of cyber deterrence and constantly improving its cyber deterrence capabilities, which must have important strategic considerations. This paper examines the evolution process of US cyber deterrence policy and divides it into four evolutionary stages according to the changes in its cyber security strategic objectives. By analyzing the characteristics of cyber deterrence policy at different stages, this paper finds that with the continuous changes in security strategic objectives, the USs cyber deterrence strategy has evolved from a purely passive defense strategy to a proactive offensive expansion one; it has completely broken through the traditional deterrence theoretical framework in the three main dimensions of coverage area, supporting means and deterrence force. By echoing offensive cyber security strategies such as “continuous engagement” and “forward defense”, the USs cyber deterrence has become an important means to maintain cyber hegemony and participate in the great power competition in cyberspace. This transformation has not achieved the goal of cyber security, but has seriously undermined the stability of cyberspace with continuous spillovers that lead to“crossdomain” security risks, and adversely affected global strategic stability.

Key words: deterrence theory, network deterrence, power competition, crossdomain deterrence, security impact

摘要： 网络威慑是维护网络安全的重要工具。既有理论研究认为网络威慑难以奏效，但美国政府却坚持强调网络威慑的重要性并不断完善其网络威慑能力，这一矛盾的做法必然存在重要战略考量。本文通过梳理美国网络威慑政策的演进过程，按照其网络安全战略目标的变化划分为四个演化阶段。通过对不同阶段网络威慑政策特征的分析，本文发现，随着安全战略目标的不断变化，美国网络威慑战略已由单纯的被动防御策略演变为一种主动进攻的扩张性安全战略，在覆盖领域、依托手段和威慑力量三个主要维度上完全突破了传统威慑理论框架。通过“持续交战”与“前出防御”等进攻性网络安全策略相互呼应，美国的网络威慑已经成为维护网络霸权、参与网络空间大国竞争的重要手段。这种转变并没有实现网络安全的目标，却严重破坏网络空间稳定，并不断外溢构成“跨域”安全风险，并对全球战略稳定构成不利影响。

关键词: 威慑理论, 网络威慑, 权力竞争, 跨域威慑, 安全冲击