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

Key Chapter Title List

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. Outcomes of Support for Ukraine
6. The Gaza War
7. Support for Ally Israel and the Liberal International Order
8. Outcomes of Support for Israel
9. Conclusion — The Inauguration of the Second Trump 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 successive conflicts of the Ukraine War (beginning in 2022) and the Gaza War (beginning in 2023) in the 2020s. These two conflicts pose severe challenges to the rules-based liberal international order. The report focuses on how the Biden administration has linked its military support operations 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 connotation of the liberal international order as 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). It points out that although the Biden administration attempted to revitalize this order with the slogan "America is back," the conflicts in Ukraine and Gaza have precisely exposed and exacerbated the crises it faces.

In the case of Ukraine, the report analyzes the triple logic behind the Biden administration's positioning of aid to 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 complete conquest. However, the aid also faces multiple dilemmas: partisan divisions and declining public support within the United States due to the prolonged war; the international community did not unite as the U.S. hoped, instead highlighting deep divisions among the Global West, Global East, and Global South; the Biden administration's caution regarding escalation risks limited the provision of certain offensive weapons, which is considered a factor leading to the stalemate in the war.

In the case of Gaza, 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 portraying Israel as a democratic nation in need of defense. While the aid militarily strengthened Israel, giving it a substantive 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 have triggered widespread international condemnation. The United States' repeated use of veto power in the UN Security Council to favor Israel and its threats of sanctions against the International Criminal Court's investigation of Israeli war criminals are widely seen as double standards, shaking the legitimacy of the rules-based order itself. Furthermore, this policy has sparked 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 has not been 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 second Trump administration shows a clearer tendency to deviate from all pillars of the liberal international order: on Ukraine, pushing for a peace that may 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, with its policy vision extremely centered on U.S.-Israel interests and exerting retaliatory pressure on international judicial institutions. 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.