Treaties, Tribunals, and Trouble: PIL & ISDS in 2025
On 8 May 2025, Allen & Gledhill LLP (Singapore) hosted a Public International Law (PIL) and Investor-State Dispute Settlement (ISDS) event titled “PIL and ISDS in a Fractured World: International and Local Perspectives.” The panel — featuring Professor Chester Brown, Professor Stavros Brekoulakis, and Peh Aik Hin — examined how institutions across the international legal system are contending with a growing sense of fragmentation.
From ISDS to the ICJ, one thing is clear: international law is still alive but its coherence is under pressure.
🍃 ISDS: In the region, but not in the room
Despite Southeast Asia’s significant outbound FDI, the region continues to account for a small fraction of global ISDS cases. Peh Aik Hin pointed to a few possible reasons: unfamiliarity with investor protections under treaty law, a strong preference for non-adversarial approaches, and the political awkwardness of suing governments.
Singapore, he suggested, is something of an exception. With a robust network of investment treaties and a well-known commitment to the rule of law, it has the infrastructure to support investor claims — if and when appetite grows.
Professor Brekoulakis added that ISDS is evolving. Originally designed to protect investors against state overreach, it is now being shaped by broader concerns, including environmental and human rights issues. But the integration of these concerns remains patchy. Even though Article 31(3)(c) of the Vienna Convention instructs tribunals to consider “relevant rules of international law,” such as climate treaties or human rights norms, the uptake has been slow and uneven.
Professor Brown, meanwhile, drew attention to the broader international system. While some institutions, like the WTO Appellate Body, are languishing, others — such as the International Court of Justice (ICJ) — are more active than ever. Yet this growing caseload, covering everything from genocide to climate disputes, raises a familiar problem: enforcement. Courts may issue rulings, but those rulings only matter if states choose to comply.
👀 Why It Matters
Fragmentation may be an academic term, but its consequences are anything but theoretical. The gaps between international institutions, treaty regimes, and legal principles are already shaping investor behaviour, and limiting the reach of international law in regions like Southeast Asia. Reform efforts are underway, but for now, international law remains a patchwork — tested, stretched, and still searching for coherence.
*The piece was contributed by Colin Seow of Nusa Chambers who attended the panel and shared his key takeaways. We’re glad to have his ear on the ground, and his sharp eye on the bigger picture.