International Relations 1919-1939
Hey students! š Welcome to one of the most fascinating yet tragic periods in European history. In this lesson, we'll explore how the world tried to build lasting peace after the devastation of World War I, only to see those efforts crumble by 1939. You'll discover how diplomacy, disarmament efforts, and international organizations like the League of Nations initially offered hope, but ultimately failed to prevent an even more catastrophic conflict. By the end of this lesson, you'll understand the complex web of international relations that shaped Europe between the wars and why these failures matter so much in understanding our modern world.
The Birth of New Diplomacy and Hope for Peace
After World War I ended in 1918, European leaders were determined never to repeat such carnage. The war had killed over 16 million people and left entire nations in ruins š. This led to what historians call "the new diplomacy" - a revolutionary approach to international relations that emphasized open negotiations, collective security, and peaceful resolution of disputes.
The centerpiece of this new approach was the League of Nations, established in 1920 with headquarters in Geneva, Switzerland. Unlike the old system of secret alliances and balance of power politics, the League promised a world where nations would work together to maintain peace. The organization had three main bodies: the Assembly (where all member nations had equal representation), the Council (dominated by major powers), and the Secretariat (the administrative arm).
Initially, the League showed real promise. Between 1920 and 1925, it successfully resolved several international disputes. For example, it settled the Aaland Islands dispute between Finland and Sweden in 1921, and helped resolve the Upper Silesia conflict between Germany and Poland in 1922. These early successes gave many Europeans hope that international cooperation could indeed replace military conflict.
The League wasn't the only attempt at creating lasting peace. The Washington Naval Conference of 1921-1922 brought together major naval powers including the United States, Britain, Japan, France, and Italy. They agreed to limit the size of their navies through specific ratios - Britain and the US could maintain the largest fleets, followed by Japan, then France and Italy. This was groundbreaking because it was the first time major powers voluntarily agreed to reduce their military capabilities! š¢
The Golden Age of International Cooperation (1925-1929)
The mid-1920s represented what many historians call the "golden age" of international relations. This period saw several major diplomatic achievements that seemed to prove the new diplomacy was working.
The Locarno Treaties of 1925 were perhaps the most significant success. Germany, France, and Britain signed agreements that guaranteed Germany's western borders as established by the Treaty of Versailles. More importantly, Germany voluntarily accepted these borders - a huge shift from the resentment that had characterized German foreign policy since 1919. The "Spirit of Locarno" created such optimism that people genuinely believed European wars were becoming impossible.
This optimism reached its peak with the Kellogg-Briand Pact of 1928, originally proposed by French Foreign Minister Aristide Briand and US Secretary of State Frank Kellogg. The pact was extraordinary - it literally outlawed war as an instrument of national policy! Initially signed by 15 nations in Paris, it eventually attracted 62 countries. While this might seem naive today, it reflected genuine belief that international law and moral pressure could prevent conflicts.
The League of Nations also expanded its influence during this period. By 1926, Germany had joined the League, and even the Soviet Union would join in 1934. The organization successfully mediated disputes in the Balkans and helped coordinate international responses to humanitarian crises. The League's Health Organization pioneered international cooperation in fighting diseases, while its efforts to combat the international drug trade showed how nations could work together on global problems.
Economic cooperation also flourished. The Dawes Plan of 1924 helped stabilize Germany's economy by restructuring its reparations payments, while American loans flowed into Europe, creating prosperity that seemed to make war economically irrational. International trade reached new heights, and many believed economic interdependence would make future conflicts impossible.
The Cracks Begin to Show (1929-1933)
Unfortunately, this golden age was built on shaky foundations. The Wall Street Crash of October 1929 triggered a global economic depression that would expose the weaknesses in the international system. As unemployment soared and international trade collapsed, the spirit of cooperation that had characterized the 1920s began to crumble.
The first major test came with the Manchurian Crisis of 1931. Japan, facing severe economic problems, invaded the Chinese province of Manchuria, claiming it was acting in self-defense. China appealed to the League of Nations for help, presenting the organization with its first major challenge from a great power.
The League's response revealed its fundamental weakness. While the Lytton Commission (sent to investigate the crisis) eventually condemned Japanese aggression, it took over a year to reach this conclusion. By then, Japan had consolidated its control over Manchuria and renamed it Manchukuo. When the League finally voted to condemn Japan in 1933, the Japanese delegation simply walked out and never returned.
This crisis was devastating for several reasons. First, it showed that the League had no effective way to stop a determined aggressor. Economic sanctions were considered but never implemented effectively, and military action was impossible since the League had no army of its own. Second, it demonstrated that major powers would ignore international law when their vital interests were at stake. Finally, it encouraged other potential aggressors by showing that the international community was essentially powerless.
The economic depression also undermined the foundations of international cooperation. As countries struggled with massive unemployment and falling living standards, they turned inward, adopting protectionist policies that destroyed the economic interdependence of the 1920s. International trade fell by approximately 25% between 1929 and 1932, while unemployment in Germany reached 6 million people by 1932.
The Collapse of Collective Security (1933-1939)
The situation deteriorated rapidly after Adolf Hitler came to power in Germany in January 1933. Hitler's Nazi ideology was fundamentally opposed to the entire post-war international system. He rejected the Treaty of Versailles, despised the League of Nations, and believed that Germany's destiny lay in territorial expansion and racial dominance.
Hitler's early moves were calculated to test international resolve. In October 1933, Germany withdrew from both the League of Nations and the World Disarmament Conference that had been meeting in Geneva since 1932. The conference itself was a failure - despite years of negotiations, nations couldn't agree on meaningful arms reductions. Instead, Germany began secretly rearming, violating the Treaty of Versailles.
The Ethiopian Crisis of 1935-1936 delivered another devastating blow to collective security. Benito Mussolini's Italy invaded Ethiopia (then called Abyssinia) in October 1935, using modern weapons including poison gas against Ethiopian forces armed mainly with spears and rifles. Emperor Haile Selassie's dignified appeal to the League of Nations, where he warned that "it is us today, it will be you tomorrow," became one of the most famous speeches in the organization's history.
This time, the League did impose economic sanctions on Italy, but they were half-hearted and ineffective. Crucially, oil - Italy's most vital import - was not included in the sanctions. Britain and France, the League's most powerful members, were more concerned with maintaining Italy as an ally against Germany than with upholding international law. The sanctions actually backfired, pushing Mussolini closer to Hitler while failing to save Ethiopia.
Meanwhile, the disarmament efforts of the 1920s completely collapsed. The World Disarmament Conference ended in failure in 1934, and nations began rearming rapidly. Germany's rearmament was the most dramatic - by 1939, the German military had grown from the 100,000 men allowed by Versailles to over 4.7 million. But other nations also increased their military spending dramatically as the international situation deteriorated.
The final nail in the coffin came with the Spanish Civil War (1936-1939) and the policy of appeasement. When Hitler remilitarized the Rhineland in March 1936, violating both the Treaty of Versailles and the Locarno Treaties, Britain and France did nothing. This encouraged further aggression - the Anschluss with Austria in 1938, the Munich Agreement that dismembered Czechoslovakia, and finally the invasion of Poland in September 1939 that triggered World War II.
Conclusion
The period from 1919 to 1939 represents one of history's greatest missed opportunities. The international system created after World War I - with its emphasis on collective security, disarmament, and peaceful resolution of disputes - offered genuine hope for lasting peace. The League of Nations, despite its flaws, achieved real successes in its early years and pioneered forms of international cooperation that continue today in organizations like the United Nations. However, the system's fundamental weaknesses - lack of enforcement mechanisms, dependence on the goodwill of major powers, and vulnerability to economic crisis - ultimately proved fatal. The failure of international relations in this period teaches us that peace requires constant vigilance, genuine commitment from all parties, and institutions strong enough to deter aggression before it begins.
Study Notes
ā¢ League of Nations (1920): First international organization aimed at maintaining world peace; had Assembly, Council, and Secretariat
ā¢ Early League successes: Aaland Islands (1921), Upper Silesia (1922), various Balkan disputes
ā¢ Washington Naval Conference (1921-1922): First voluntary arms limitation agreement; established naval ratios between major powers
ā¢ Locarno Treaties (1925): Germany accepted western borders; created "Spirit of Locarno" optimism
ā¢ Kellogg-Briand Pact (1928): 62 nations agreed to outlaw war as instrument of policy
ā¢ Wall Street Crash (1929): Triggered global depression that undermined international cooperation
ā¢ Manchurian Crisis (1931-1933): Japan invaded Manchuria; League's weak response encouraged further aggression
ā¢ Hitler's rise (1933): Germany withdrew from League and Disarmament Conference; began secret rearmament
ā¢ Ethiopian Crisis (1935-1936): Italy invaded Ethiopia; League sanctions were ineffective
ā¢ Spanish Civil War (1936-1939): Became proxy conflict between fascist and democratic powers
ā¢ Appeasement policy: Britain and France failed to stop Hitler's early aggressions (Rhineland 1936, Austria 1938, Czechoslovakia 1938)
ā¢ Key weakness of League: No enforcement mechanism or army; dependent on member nations' goodwill
ā¢ Economic factor: Depression destroyed economic interdependence that had supported 1920s cooperation