Within the highly politicized field of international-legal theory, Biden’s victory has been hailed as signalling the ‘restoration’ of a rules-based order. Though practitioners are cautioning each other not to count on a ‘full re-set’, their hope is that multi-lateral legal sanctions with Washington’s full force behind them will be back in play.footnote1 Under the Trump Administration, Ivy League nostalgia for an era in which us imperialism went hand-in-hand with international legal sanction was palpable. From Yale, Harold Koh—legal architect of Obama’s assassination-by-drone programme—had warned of a potentially permanent shift in America’s relationship to international law and its institutions.footnote2 Such lamentations were accompanied by a genre of redemptive histories—Isabel Hull’s A Scrap of Paper (2014) and Philippe Sands’s East West Street (2016) stand out—insisting on international law’s progressive power and its ability once more to put the world to right.

To examine the case they are making, it may be helpful to return to a work that has perhaps garnered more acclaim and popular promotion in this field than any other. On publication, The Internationalists by Oona Hathaway and Scott Shapiro was showered with praise.footnote3 The Economist found it ‘an impassioned history of how the liberal international order came into being and why it must be defended as never before.’ ‘Like The Clash of Civilizations and The End of History, this brilliant book lays out a vision that makes sense of the world today’, declared Steven Pinker. In the Financial Times, Margaret MacMillan welcomed its ‘robust defence of liberal internationalism’. It continues to earn plaudits, cited approvingly in February by the Canadian Supreme Court.footnote4

Both authors are established scholars in their respective fields—international law for Hathaway, jurisprudence for Shapiro—yet the book is a departure in many ways from their earlier work. Hathaway enjoyed Circuit and Supreme Court clerkships before returning to Yale Law School, her alma mater, as a leading proponent of empiricist approaches to the study of international law. Her early work brought a distinctly International Relations approach—abstract models and cross-national data analysis—to questions of international legal compliance. A stint inside the Beltway saw her offering counsel at Obama’s Department of Defense, her curriculum vitae proclaiming her ‘Top Secret’ clearance. The turn to international legal history is all the more striking for Shapiro, a legal philosopher whose work prior to The Internationalists was squarely in the realm of analytical jurisprudence; a previous book, Legality (2011), concerned the metaphysics of legal norms and advanced a concept of law as social planning.

To understand today’s international legal order, they argue, we must grasp its origins. These they trace to the 1928 General Treaty for Renunciation of War as an Instrument of National Policy, better known as the Kellogg–Briand Pact or simply the Paris Peace Pact. They acknowledge the ‘renunciation of war’ was not an immediate success; within a dozen years of the Paris Peace Pact, Japan had invaded China, Italy conquered Ethiopia, Germany invaded Poland and most of the signatories had plunged into the multiple conflagrations of World War Two. Nevertheless, The Internationalists insists, the Pact was one of ‘the most transformative events of human history’, the hinge around which an old order of violent, regressive inter-state warfare swung into a peaceful, prosperous New World Order.footnote5 This is the story of liberal internationalism’s emergence told with a new twist: to the stock markers of progress—free trade, democracy, international cooperation—the authors add the outlawry of war.

The Internationalists begins in 1603, with Dutch merchants’ seizure of a Portuguese great-ship, laden with gold, silk and spices, off the coast of Singapore. The Portuguese had hitherto dominated trade with the region and drove out any Dutch vessels that tried to operate there. The Dutch captain, Jacob Van Heemskerck, was presented with an opportunity for plunder. He towed the Santa Catarina back to Amsterdam and delivered it to the Dutch East India Company which, after a few legal niceties, auctioned off the goods. To silence concerns that this was mere freebooting, the Company commissioned a 21-year-old legal prodigy, Hugo Grotius, to justify Van Heemskerck’s act as the taking of a legitimate prize. The result was the 500-page Commentary on the Law of Prize and Booty, an extended study of the laws of war. Grotius turned to the just-war tradition of Cicero, Augustine and Aquinas, in which war is morally permissible to remedy a wrong. Within the jurisdiction of a state, he observed, individuals agree through the social contract to replace war with public courts, appealing to the sovereign authorities for redress. However, ‘ordinary remedies do not serve in an extraordinary situation’. In the political vacuum of the high seas, a victim can appeal to no higher authority and thus maintains the right to wage war to remedy a wrong. How, though, had Van Heemskerck been wronged? Grotius offered a vitae of Portuguese atrocities: these ‘assassins, poisoners, and betrayers’ had committed ‘abominable cruelty’ in their efforts to deter the Dutch from the East Indies trade. To the benefits of that trade, Grotius insisted, ‘nature has given all men free access’; the Dutch also had a right to commerce and Van Heemskerck was simply asserting that right.footnote6

Beyond a defence of Van Heemskerck, Grotius was thus laying the juridical foundation for Dutch commercial expansion tout court. The authors argue that this thinking informed his more famous 1625 treatise, On the Law of War and Peace [De iure belli ac pacis]. This, too, they suggest, was fundamentally ‘an effort to justify war’. Where many have seen in Grotius a desire to meliorate war’s worst horrors, they paint him as its chief apologist—Kant’s ‘sorry comforter’ of warmongers—and his work ‘an unabashed defence of the morality of war’.footnote7 The simple principle that animated the Old World Order was that war represented a legitimate method to enforce one’s rights. The Internationalists surveys sovereigns’ reasons for declaring war from the late 15th century to 1914. These ranged from the idiosyncratic—Charles’s alleged theft of Maximilian’s wife—to the prosaic: self-defence, enforcement of treaty obligations, collection of debts, protection of trade interests, defence of religious rights and violations of international law. Under the Old World Order, war was international law’s principal means of enforcement.

From this first-order permissiveness towards war, four rules are said to follow. First, the right of conquest. In principle, Grotius thought that conquest, like war, should be permissible only to prevent or redress the violation of a right. But who was to judge the justness of this? Each belligerent would inevitably claim justice on its side. The result would be legal uncertainty around property rights. The Internationalists dubs Grotius’s solution the ‘Might is Right’ principle: success alone creates legal rights in war. Soldiers become the rightful owners of booty, states the legitimate sovereigns of conquered territory simply by virtue of victory. The ‘practical perspective’ of commerce required an embrace of the simple maxim that ‘winning in war meant winning in law’. A second consequence of the legitimacy of war was impunity for those waging it. If states enjoyed the legal right to wage war, their leaders could hardly be punished for it. Napoleon, for instance, enjoyed impunity—and retained his imperial title, albeit only as Emperor of Elba—even in defeat. Exile was the cost of losing the war, not punishment for any crime. Indeed, his later imprisonment on St Helena troubled even his detractors: on what legal grounds could this be justified?footnote8