Did Outlawing War Actually Work?

If anyone in the world is predisposed to appreciate the 1928 Kellogg-Briand Pact, it’s me. As a parochial Minnesotan, I’m happy to claim one of our native sons as both U.S. Secretary of State and Nobel Peace Prize winner. My undergraduate honors thesis featured Frank Kellogg’s co-laureate, French foreign minister Aristide Briand, who went on from that negotiation to propose an early plan for European unity. And who doesn’t like the idea of states voluntarily renouncing warfare as a means of settling international disputes?

“But wait,” you say, wracking your brain for some dim memory of a long-ago history class, “I thought the Kellogg-Briand Pact was an abject failure, with all but one of its signatories at war with one another within just over a decade.”

Think again, say Yale law professors Oona Hathaway and Scott Shapiro. Their new book, The Internationalists: How a Radical Plan to Outlaw War Remade the Worldisn’t out yet, but over the weekend they previewed their research and argument in an op-ed for the New York Times:

Though the pact may not have ended all war, it was highly effective in ending the main reason countries had gone to war: conquest. This claim is supported by an empirical analysis we recently conducted of all the known cases of territorial acquisition during military conflict from 1816 to the present.

From the end of the Napoleonic Wars to the signing of the pact in 1928, they find, “the average state… had a 1.33 percent chance of being the victim of conquest in any given year” (or, once per human lifetime) with almost 115,000 square miles of land (equivalent to Italy) conquered annually on average. Since 1928, the odds have plummeted to 0.17%, with the major shift taking place between 1928 and 1948.

I’m sure their argument is developed with much more nuance in the book, but as presented in the op-ed… Well, I’m not convinced.

The first obvious problem is that correlation isn’t causation. There was actually an enormous amount of land conquered after 1928 — and it was only returned because the most terrible war in history compelled its return… and then only after Fascist Italy, Nazi Germany, and Imperial Japan were forced into submission, in large part by a Soviet state that returned little of the land it had conquered between 1939 and 1945 and by an American state that had little need to conquer more land when it could easily conquer markets.

If there was less conquest after World War II, it’s as likely because of the cold realities of the Cold War than the now-warmed hearts of statesmen. By the time North Korea’s gambit in June 1950 was turned back, both sides had access to nuclear weapons, making it unclear that the acquisition of territory could ever be the objective of a great power war. If we think counterfactually and uninvent those devices, is it likely that the rate of conquest remains so low? Or could we easily imagine superpowers continuing to invoke their security concerns to justify conquests within their spheres of influence? (Would Cuba have remained independent after the 1959 revolution threatened American interests? Would Taiwan still be independent of Beijing? How much bigger would the Soviet empire have grown?)

Hathaway & Shapiro, The Internationalists“By crediting the Kellogg-Briand Pact with changing state behavior,” admit Hathaway and Shapiro, “we do not deny the importance of many other causes that have been offered for the end of conquest and decline of war, such as the advent of nuclear weapons and the considerable rise in free trade. But these explanations are incomplete because they tacitly assume the idea of the pact that might no longer makes right.”

It’s never a bad idea to focus attention on the diplomatic history of the 1920s, which we’re tempted to see as a series of hapless failures leading up to the inevitability of a Second World War. And insofar as it goes, I think it’s fine to consider Kellogg-Briand as extending the embrace of a principle that had been developing for decades before 1928.

Just keep in mind that none of those governments that affirmed that “might no longer makes right” demonstrated any real commitment to that principle. Just ask all the peoples around the world not represented at that conference in Paris, being under various imperial thumbs at the time. (The only non-Western countries there were Japan — which already occupied Korea and Taiwan and was on the verge of starting its conquest of East Asia — and India — that is, its emperor, a.k.a. the “King of Great Britain, Ireland, and the British Dominions beyond the Seas.”) Or ask the minority populations within the signatory countries, many of which continued to suffer violent repressions at the hands of their own governments, few of which were democratically elected. (Talk amongst yourselves as to whether the segregated country represented by Frank Kellogg qualifies.)

Of course, Japan, the U.S., and the European powers that signed Kellogg-Briand didn’t regard what happened in their empires as being covered by the pact, which only dealt with war between them, not within what they took to be their sovereign territories. I’m not about to dig into all the data Shapiro, Hathaway, and their law students gathered, but I wonder how they coded the acquisitions of territory by colonial expansion in the 19th century. If Kellogg-Briand made such a difference in how states thought about the right of war, why did European empires continue to maintain their power after 1928 by making — or threatening — war on subjugated peoples? If it made such a difference, why did none of its signers do anything to stop Adolf Hitler (chancellor of a signatory power) from making war on a minority of his own people for over six years before he made war on the rest of Europe?

If we’re going to give international law any credit for modifying state behavior, then I’d focus on December 1948’s one-two punch of the UN convention against genocide and the Universal Declaration of Human Rights, in which states theoretically accepted curbs on their ability to use their monopolies of violence within their sovereign borders. But more so, I’d look to the onset of decolonization, in which countries like France and Britain were finally compelled by military defeat or the potential cost of military success to live up to the principle of might not making right.