Cybersecurity Alliances: Applying Mutual Defense Treaties to Combat Cyber Threats

Line of Effort 5: Affirm Application of Mutual Defense Treaties with Certain Allies to the Cyber Domain

In line with the long-standing U.S. recognition that existing international law applies in cyberspace, obligations under treaties and other international agreements may apply in cyberspace. Over the past several years, the United States and certain allies have made public statements affirming the application in cyberspace of obligations in their respective mutual defense treaties, including the 1951 Security Treaty between Australia, New Zealand and the United States (ANZUS) (2011); the North Atlantic Treaty (2014); the Treaty of Mutual Cooperation and Security between the United States and Japan (2019); and the Mutual Defense Treaty between the United States and the Republic of Korea (2023). The Departments of State and Defense will continue to work together with allies to engage in pre-contingency planning and to raise awareness further with alliance partners that existing mutual defense treaties may apply in cyberspace and that cyberattacks rising to the level of an armed attack may trigger mutual defense obligations under such treaties.