The  post-World  War  II  international  legal  order  has  been  built  on  the  foundations of multilateralism,   cooperation,   and   the  rule  of   law.   International   trade   and   investment, environmental  protection,  criminal  accountability, and  cross-border  governance  have  all  been developed through treaties, customary norms, and international institutions designed to regulate state conduct and advance common global interests. However, in recent years, this multilateral consensus has come under increasing strain due to a growing wave of state unilateralism—a trend in which states act independently of, or even contrary to, established international legal norms and institutional mechanisms.

Unilateralism  in international  economic  law has  become  particularly  visible.  A  notable example is the imposition of broad trade tariffs under the so-called “Liberation Day” policy by the United States in April 2025. This policy introduced sweeping import tariffs justified based on national economic security, prompting retaliatory measures and WTO complaints. While such acts are often framed as protecting national interests, they challenge the credibility and effectiveness of multilateral institutions like the World Trade Organization (WTO) and question the stability of international trade and investment regimes.

Beyond trade, unilateral action is increasingly shaping other branches of international law. Some states have unilaterally withdrawn from Bilateral Investment Treaties (BITs) or terminated Investor-State Dispute Settlement (ISDS) mechanisms in international investment law, citing concerns over regulatory autonomy and public interest protections. This trend has raised legal uncertainties and increased fragmentation in the investment landscape. In international climate change law, state unilateralism is reflected in instances such as the withdrawal from global environmental accords, including the United States’ past withdrawal from the Paris Agreement, or countries pursuing energy policies at odds with global emission reduction commitments. These actions erode collective environmental responsibility and hinder the enforceability of climate obligations. In international criminal law, certain powerful states have rejected or failed to cooperate with international tribunals, such as the International Criminal Court (ICC). Non-ratification, refusal to extradite suspects, and shielding of nationals from prosecution are unilateral decisions that compromise the global project of accountability for mass atrocities. In border securitisation and migration,  states have increasingly  relied  on  unilateral  and  extraterritorial  measures—such as pushbacks at sea, border walls, or third-country processing of asylum seekers—raising complex legal and ethical issues under international refugee and human rights law.

These varied manifestations of unilateralism pose serious challenges to international law’s coherence, legitimacy, and enforceability. They also reflect deeper tensions between the assertion of state sovereignty and the demand for international cooperation in addressing complex transnational issues.

This international conference is convened to critically assess the resurgence of unilateralism in the development and enforcement of international law. It examines how unilateral state practices reshape legal norms across different domains—particularly trade, investment, climate, criminal accountability, and border governance. The conference will also explore the implications of these developments for the legitimacy of international institutions, the evolution of global legal frameworks, and the prospects for renewed multilateralism in an increasingly fragmented world order.