Expert Opinion of the International Law Association: U.S. Military Assistance in the Wars in Ukraine and Gaza

List of Key Chapter Titles

1. Introduction
2. What is the Liberal International Order?
3. The Ukraine War
4. Support for Ukraine and the Defense of the Liberal International Order
5. Consequences of Support for Ukraine
6. The Gaza War
7. Support for Ally Israel and the Liberal International Order
8. Consequences of Support for Israel
9. Conclusion — The Inauguration of Trump's Second Administration and the Future of Military Support —

Document Overview

This report aims to systematically examine the military assistance provided by the United States as a non-direct party to the Ukraine War (beginning in 2022) and the Gaza War (beginning in 2023), which erupted successively in the 2020s. These two conflicts pose severe challenges to the rules-based liberal international order. The report focuses on how the Biden administration linked its military aid actions for Ukraine and Israel with its diplomatic commitment to defending the liberal international order, and assesses their actual effectiveness and inherent contradictions.

The report first defines the core elements of the liberal international order, namely an international system based on political liberalism (liberal democracy and human rights), economic liberalism (free trade and interdependence), and liberal internationalism (rules-based multilateral cooperation). The report points out that although the Biden administration attempted to revitalize this order with the slogan "America is back," the conflicts in Ukraine and Gaza precisely exposed and exacerbated the crises it faces.

In the Ukraine case, the report analyzes the threefold logic behind the Biden administration's positioning of aiding Ukraine as a "battle to defend the liberal international order": upholding the rules-based international order, defending democratic systems, and ensuring the security and stability of key regions (Europe and East Asia). Military assistance effectively strengthened Ukraine's defensive capabilities and prevented Russia's full-scale conquest. However, the aid also faced multiple dilemmas: domestically in the U.S., partisan divisions and declining public support emerged due to the protracted war; internationally, instead of uniting as the U.S. hoped, profound divisions between the "Global West," "Global East," and "Global South" were highlighted; the Biden administration's caution regarding escalation risks limited the provision of certain offensive weapons, which is believed to have contributed to the stalemate in the conflict.

In the Gaza case, the report explores the motivations behind the unprecedented scale of U.S. military aid to Israel: the special alliance relationship, domestic pro-Israel public opinion, and the portrayal of Israel as a "democratic nation" in need of defense. While the aid militarily strengthened Israel, giving it a substantial military advantage over Hamas, it severely damaged the credibility of the United States as a defender of the liberal international order. The large-scale civilian casualties and humanitarian disaster caused by Israeli military operations triggered widespread international condemnation. The U.S. repeatedly exercised its veto power in the UN Security Council to favor Israel and threatened sanctions against the International Criminal Court for investigating Israeli war crimes. These actions were widely seen as "double standards," shaking the legitimacy of the "rules-based order" itself. Furthermore, this policy provoked a strong backlash among young voters and Arab-American voters domestically, becoming one of the factors influencing the outcome of the 2024 election.

The conclusion of the report states that the Biden administration's military assistance failed to effectively achieve its declared goal of defending the liberal international order. In Ukraine, the aggressor was not held accountable; in Gaza, while promoting a ceasefire, the U.S. continued to aid Israel, which is suspected of violating international law, thereby participating in the process of weakening the liberal international order. The newly inaugurated Trump second-term administration shows a clearer tendency to deviate from all pillars of the liberal international order: on Ukraine, pushing for a "peace" that might tacitly accept Russia's territorial gains through force, sacrificing Ukrainian sovereignty and democratic prospects; on Gaza, while promoting a ceasefire, ignoring Palestinian self-determination rights and international law, its policy vision is extremely centered on U.S.-Israeli interests and exerts retaliatory pressure on international judicial bodies. The report ultimately warns that the weakening of the foundations of liberal democracy within the United States makes it difficult for the country to continue serving as the core defender of the liberal international order, and the future of that order faces great uncertainty.

※This report is based on research results funded by JSPS KAKENHI Grants JP20H01462 and JP25K00608.