Leonard Smith shows that the distinction between“voluntary” and “compulsory” population exchanges in the Balkans and Anatolia was often more apparent than real. The Great Powers sought to keep both exchanges at arm’s length, and ethno-nationalism proved the deciding issue in both cases.

If the successors to the multinational empires that had lost the Great War were to be independent, homogeneous ethno-national states, there were always only two options—tailor boundaries to suit peoples, or peoples to suit boundaries. Peacemakers did some of each, with results that pleased few. By the time peacemaking got to the Treaty of Lausanne, an exhausted and changing international system favored the latter as the path of least international resistance. “Population exchange,” what later in the 20th century would be called “ethnic cleansing” did not come from nowhere. A supposedly “voluntary” exchange between Greece and Bulgaria written into a convention added to the Treaty of Neuilly of November 1919 paved the way to the “compulsory” exchange detailed in the convention appended to the Treaty of Lausanne of July 1923. 

In the end, the similarities between the two exchanges mattered at least as much as the differences.

Both conventions had the effect of bestowing international legal recognition on population transfers that largely had already taken place or would likely have taken place anyway. Even the “voluntary” Greek-Bulgarian exchange offered minorities the unappealing choice of either remaining in states that had expressed a public preference that they leave, or migrating as refugees to a new land, often with resentful neighbors with whom they happened to share a common language and/or religion. The “compulsory” Greek-Turkish exchange took place against the backdrop of renewed war, in which the new ethno-Turkish state partly reversed the outcome of the Great War in Anatolia. Terrified Greeks fled violence, while Muslims feared reprisals in an expanded and bellicose Greece. 


The conventions on population exchange also served to articulate the relationship of the Great Powers to the outcome of the Great War in the Balkans and in Anatolia. Given the endless tangles of drawing borders to suit ethnicities in multiethnic Eastern Europe, and the structural as well as procedural impossibilities of staging plebiscites perceived as “fair” by all, let alone interpreting the results of plebiscites, the peacemakers came to see exchanges as a simple if rough alternative. 

But conceding population transfers and legitimizing them through appending conventions to peace treaties, in effect, meant that the Great Powers at the center of peacemaking subcontracted or simply relinquished the authority to structure successor states in certain regions. Everyone understood at the time that transferring thousands of people from one sovereignty to another was going to prove a messy business. Consequently, from the first Greek proposal to the New States Committee of the Paris Peace Conference in July 1919 to establish mixed commissions to facilitate the Greek-Bulgarian transfer, Great Powers fretted over whether endorsing the commissions meant endorsing transfers that everyone knew were less than “voluntary.” 

No one wanted to take the blame for it.  The crocodile tears accompanying the famous words of British Foreign Secretary Lord Curzon spoke for many.  

The stakes were much higher with the Conference of Lausanne, which while part of peacemaking after the Great War was legally distinct from the Paris Peace Conference. The Lausanne conference itself proceeded from the lost war between the Great Powers and their Greek proxy and Turkey. With demobilization proceeding apace and with mandates to secure in the Arabic-speaking former Ottoman lands, the British and the French needed peace in Anatolia. The Greeks, the Turks, and the Great Powers all wanted a Greek-Turkish population transfer by any means necessary as an exit strategy. 


Curzon “deeply regretted” a compulsory exchange, referring to it as “a thoroughly bad and vicious solution, for which the world would pay a heavy penalty for a hundred years to come.” Yet neither Curzon nor any of his counterparts would seek any other solution. Much ink, in fact, would be spilled in subsequent years assigning or refuting blame for the exchange attributed to one of the world’s first genuinely international civil servants, and an apparatchik in the exchange, Fridtjof Nansen.

In the end, the Great Powers kept both exchanges at arm’s length by confining them to conventions. There was in fact no clear distinction at the time between conventions and treaties. Only Greece and Bulgaria, and Greece and Turkey, actually signed the conventions, which nevertheless had the same force under international law as the treaties proper. The term “convention,” distinct from “treaty,” helped establish plausible denial for the Great Powers in the grim business of population exchange.

The most important difference between the two conventions lay in the criteria for assigning “ethnicity.”

The convention providing for the Greek-Bulgarian exchange called for self-designation—an individual plebiscite. Migrants would simply declare their ethnicity to the representative of a mixed commission. The commission itself would serve primarily as an honest broker in the disposition of moveable and immoveable property. 


The Greek-Turkish convention defined ethnicity as religion pure and simple. “Greek” and “Turk” had ceased to be a matter of national spirit, culture, language, or even political loyalty. Least of all could ethnic identity remain a matter of personal choice. Religion became the exclusive marker of ethnicity, by state decree ratified internationally through the conventions. The mixed commissions also became the instrument of state policy, and the instrument of classifying people and property. Yet even this simple, brutal means of assigning difference had limits in disentangling peoples who had lived alongside one another for centuries. Christians in Istanbul and Muslims in Western Thrace were excluded from the exchange. Other Christians, notably the substantial community of Pontic Greeks in Eastern Anatolia, were not.

To the extent that peacemaking after the Great War was ever about building a liberal international legal order based on tolerant, inclusive, self-determined successor states, the history of population exchanges charts the rapid decline and fall of that order. Ethno-nationalism became ever more firmly established a legitimizing principle in the postwar order, with sinister consequences to follow. “Ethnic cleansing” could scarcely have its present meaning without the exchanges following the Great War having laid the groundwork. 


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