The outcome of the First World War – often called “the Great War” prior to the outbreak of a second world war – had a profound impact on international relations. The war’s end saw the demise of some of Europe’s monarchies (including in Russia) and most formidable empires, including the Ottoman and Austro-Hungarian Empires. It also resulted in the emergence of newly-established nations like Czechoslovakia, Poland (which had been a recognized ethnicity but which suffered under imperial occupation for centuries), the Baltic states of Lithuania, Latvia and Estonia, Yugoslavia (which constituted its own little empire-of-sorts that would violently break apart after the Cold War had ended), and Finland. The modern nation-state of Turkey was formed out of the remains of the Ottoman Empire, Austria and Hungary were established as independent states. The end of the war, in short, resulted in monumental disruptions to the old order that had dominated European politics for hundreds of years.
The inter-war period – the years between the 1918 armistice that ended World War I and the start of World War II (usually dated with the invasion of Poland in 1939) – ushered in, as a direct consequence of the disintegration of the old empires and the emergence of new nation-states, a fundamental transformation in international diplomacy. U.S. President Woodrow Wilson’s commitment to collective security, while defeated with regard to U.S. participation by mainly-Republican senators who opposed the League of Nations out of concerns for U.S. sovereignty and potentially costly foreign commitments, was still-born, leaving a chaotic vacuum in which each country maneuvered for advantage and for survival. The Treaty of Versailles, of course, imposed stringent conditions on Germany that contributed to the popular support enjoyed by the fascists led by Ernst Rohm and Adolf Hitler, and France huddled down behind its “invulnerable” defensive fortifications along the Franco-German border labeled for French Minister of War Andre Maginot, and Britain watched warily but ineffectually as Germany rebuilt its military, militarized its industries, and began to assert itself internationally. The financial costs associated with World War I emptied government coffers in Britain, France, and Russia, leaving each nation economically destitute only to be subsequently hit by the Great Depression. Germany’s economy continued to suffer from the financial burden associated with war reparations, and hyper-inflation further emboldened the fascist movements. Plus, ethnic Germans who fled the newly-established nations of Czechoslovakia and Poland added to Germany’s already dire economic situation, with unemployment a huge problem. Amidst all of this, international diplomacy was nonexistent.
International diplomacy played a complicated role in the inter-war period with respect to national identities. States that emerged from the wreckage of World War I were thrust into the awkward and dangerous situation of having to protect their new-found sovereignty from outside encroachment. The frontiers dividing Russia, Romania and Hungary were all rearranged in accordance with the contemporary balance of power among the three nations. Hitler would threaten (and ultimately act on that threat) to “regain” ethnic German-populated regions of Europe like the Sudetenland of Czechoslovakia and the region of Upper Silesia granted to Poland following Germany’s defeat in the war. The treaties (e.g., the Treaties of Neuilly, Trianon and Sevres) that were concluded following the armistice were all imposed by victors over vanquished, thereby guaranteeing that unresolved and highly flammable disputes remained to fester in the context of economic catastrophe. As German industrial and military power increased – and the two went together, as industrialization was essential for construction of a modern military – the post-World War I arrangements began to fragment. International diplomacy became increasingly oriented towards concerns about German rearmament, with the Russians extremely frightened about the prospects of a resurgent and hostile Germany. The newly-established states were all threatened with encroachment or invasion because of vindictive motivations that underlay many of the post-war arrangements, a situation particularly precarious in Yugoslavia, with a Croatian population that was overwhelmingly pro-German and a Serbian population that was close to Russia.
International diplomacy in the inter-war years enabled a great expansion in the expression of nationalist sympathies. The new states were all expressions of those sympathies. Unfortunately, the provisions of the treaties that grew out of World War I, including the Treaty of Versailles, however well-intentioned, collectively set the stage for the conflicts that followed. Nationalism was and remains a potent force, and the drawing of international borders all too often reflected disregard for the full extent of nationalist fervor and all too often represented diplomatic machinations of the great powers of the time.