Collective defence in NATO: A legal and strategic analysis of Article 5 in light of the war in Ukraine

Traces how NATO’s collective-defence mission under Article 5 — long overshadowed after the Cold War — has returned to the fore since Russia’s 2014 annexation of Crimea and 2022 invasion of Ukraine. Using a law-in-context approach, the paper examines Article 5 from both legal and strategic angles to assess how credible NATO’s mutual defence commitment is in practice. (DELI Working Paper No.2/2024)