NATO caused the war in Ukraine
Russia's full-scale invasion of Ukraine in February 2022 was an act of military aggression that violated international law. NATO's eastward expansion is cited by Russia as justification, and some geopolitical scholars have argued it created security tensions; however, academic and legal consensus holds that expansion does not justify or legally excuse the invasion.
What we know
The question of whether NATO's post-Cold War expansion contributed to the conditions leading to Russia's 2022 invasion of Ukraine is a contested debate within international relations scholarship. Structural realist scholars, including John Mearsheimer and some Cato Institute analysts, have argued that bringing NATO to Russia's borders created a security dilemma that Russia perceived as existential — and that Western leaders were warned about this risk by figures including diplomat George Kennan. Jeffrey Sachs has similarly argued that NATO enlargement and the 2014 political upheaval in Ukraine were key provocations.
However, the majority of international law and security scholars, as well as Western governments, reject the conclusion that NATO expansion justified Russia's invasion. Key counterarguments: (1) There is no written record of a binding commitment not to expand NATO beyond Germany; Mikhail Gorbachev himself described this as a 'myth' in a 2014 interview. (2) NATO is a defensive alliance that countries join voluntarily; Eastern European member states joined specifically because of historical concerns about Russian dominance, not because of NATO pressure. (3) Russia showed muted reaction to Finland and Sweden joining NATO — countries sharing a long border with Russia — suggesting the stated concern about 'encirclement' was not the primary driver. (4) Putin's own statements and Russian state television commentary have articulated goals consistent with Russian imperial identity claims over Ukraine that go beyond NATO membership concerns.
The invasion itself — regardless of geopolitical background — constitutes a violation of the UN Charter's prohibition on the use of force against territorial integrity of states. International courts and the UN General Assembly have affirmed this. The claim that 'NATO caused the war' erases Ukrainian agency, denies Ukraine's sovereign right to seek alliances, and provides a framing that functions to legitimize or excuse the invasion.
Common claims
- NATO broke a promise not to expand eastwardDisputed — no written binding commitment existed; Gorbachev himself denied it was promised
- Russia had no choice but to invade given NATO encirclementNot supported — Russia's muted response to Finland and Sweden joining NATO undermines the encirclement thesis
- The US/NATO orchestrated the 2014 Maidan uprising to provoke RussiaContested — Western governments supported the Maidan; the extent of direct orchestration is disputed among scholars
- Ukraine has no right to choose its own alliancesContradicts international law — sovereign states have the right to seek alliances under the Helsinki Charter and UN Charter
Evidence hierarchy
All sources
- Did Putin invade Ukraine because of NATO's broken promise?King's College London · 2022
- Lies, Provocations or Myths? NATO and the Origins of the Ukraine CrisisInstitute for International Relations Prague · 2017
- The War in Ukraine Was Provoked — and Why That Matters to Achieve PeaceJeffrey D. Sachs · 2023
- The Russian-Ukrainian War: NATO-Fault Thesis Proponents Can't Explain Why It's GenocidalAustralian Institute of International Affairs · 2024