The Vietnam War and International Law

Abstract

There have been thousands of histories of the Vietnam War, but none assigns a pivotal role to international law. Research nevertheless indicates that, more than any history has acknowledged, both state actors and outside observers looked at the war through the prism of international law, whether it came to the legality of American intervention in the first place or to the constraints both sides adopted over the long years of struggle.

Perhaps the most important fact about international law, however, is that it never became a primary focus of how choices were made – not in the hallways of power, not on the fields of battle. Even in garnering public support for opposition to America’s intervention, international law played a small role. “It is a humbling realization of no small moment,” observed Richard Falk in 1973 – at the time the most energetic figure to try to bring the field’s materials to bear on the war – “to acknowledge that only international lawyers have been paying attention to the international law arguments on the war.” And yet the aftermath of Vietnam showed that it was indeed a pivotal event in the history of international law. In the long run it changed forever how war is fought and how it is talked about.

This chapter offers a synthetic overview of the range of issues in international law that arose during the course of the Vietnam War, especially as Americans took over from the French after Điện Biên Phủ in 1954 and moved, seemingly inexorably, toward massive escalation between 1964 and 1973. The chapter begins by seeking to discern what law applied to the conflict, emphasizing the points of agreement between actors on both sides and observers of different political sympathies concerning the legal status of South Vietnam. The chapter then asks – relying on the prevailing understanding of prior diplomatic events, as well as evolving notions of statehood – what claims were possible and plausible when it came to the legality of American intervention in the war. Next, the chapter addresses the different kinds of warfare in which the United States engaged, from its bombing campaigns over North Vietnamese territory and waters to the changing forms of its counterinsurgency in the South and, later, across the Cambodian border. Finally, the chapter concludes by examining the legal impact of Vietnam: not only how it led to the most significant substantive development of the laws of war since the Geneva Conventions, but also, and equally importantly, how it ensured that international law would play (for good or ill) a central role in debate over and analysis of all future conflicts – particularly those in the current era, in which the United States has returned to counterinsurgent warfare abroad.