International relations (1919–1939)

International relations (1919–1939) covers the main interactions that shaped world history during the interwar period. This time followed the diplomatic history of World War I and led up to the start of World War II.

Key events included solving issues left from the war, like reparations owed by Germany and setting new boundaries. There was also American involvement in European finances and efforts to reduce weapons. The League of Nations tried to help but faced many challenges.

The period saw new countries forming and struggling to relate to older nations. There was also tension between the Soviet Union and other countries with different economic systems. Efforts for peace and reducing weapons were made, but the Great Depression starting in 1929 made things harder.

The world also faced problems like the collapse of international trade and the fall of democratic governments. Japan became more aggressive toward China, and fascist leaders in Italy and Germany made bold moves. The Spanish Civil War was another conflict during this time.

As tensions grew, countries like Germany expanded into areas such as the Rhineland, Austria, and Czechoslovakia. This period ended with desperate efforts to rearm as another world war seemed closer.

Background

Main articles: Diplomatic history of World War I, Aftermath of World War I, Interwar period, and [International relations (1814–1919)](/wiki/International_relations_(1814–1919)

After World War I, countries worked to solve problems left by the war. They dealt with money owed by Germany, drew new borders, and tried to keep peace with groups like the League of Nations. Many new countries formed, and there were big changes in how countries traded and worked together.

Peace and disarmament

There were no large wars in the 1920s. Small conflicts happened, but they did not grow into bigger problems. Many countries worked hard for peace. Leaders believed that working together through groups like the League of Nations could help solve problems without fighting.

The League of Nations was created in 1919 to keep peace and help countries talk out their differences. However, some big countries like the United States, Germany, and the Soviet Union did not join at first, which made it harder for the League to work well. The League tried to stop fights, like when Japan invaded Manchuria and when Italy invaded Ethiopia.

Countries also tried to reduce their weapons. The Washington Naval Conference in 1921 led to treaties that limited the size of navies. Later, the London Naval Treaty in 1930 continued these limits.

In 1925, the Locarno Treaties helped improve relations between European countries. In 1928, many countries signed the Kellogg–Briand Pact, promising not to use war to solve problems.

The use of poison gas in war was also outlawed by the Geneva Protocol in 1925, which most countries agreed to follow.

Europe

The time between the two World Wars had big changes in how countries worked together. The United Kingdom had to keep its power while new strong countries like the United States grew. France worked to make friends to stop threats from Germany. New movements called fascism started in Italy and Germany, bringing new and aggressive rules. The Soviet Union tried to find its place with both rich and fascist countries.

The Great Depression in the 1930s made things hard for many countries. It caused money problems and political trouble. Many countries turned to authoritarian leaders, and talks to reduce weapons often failed. The League of Nations tried to keep peace, but tensions grew until they led to World War II. New countries formed in Eastern Europe, and the balance of power changed, setting up for bigger conflicts later.

Main articles: History of the foreign relations of the United Kingdom and United Kingdom and the League of Nations

Further information: Timeline of British diplomatic history and History of the United Kingdom

United Kingdom

The UK had a hard time keeping its power in the 1920s and 1930s. It often needed money help from the United States. Important events included the Paris Peace Conference of 1919, where the UK tried to make rules for Germany less harsh. The UK joined the League of Nations, but it did not always work well.

Problems at home hurt its plans for other countries, and friends like Canada, Australia, South Africa, and New Zealand became more independent. The UK tried to keep peace with agreements on ships and with the Locarno treaties of 1925 to make Germany feel better.

The Great Depression hurt the UK's money, so it changed its trade rules and put taxes on imports. Talks to reduce weapons stopped, and big countries started building up their armies again. The UK tried a policy of appeasement toward Germany and Italy in the late 1930s to avoid war, but this did not work as fights grew bigger.

Further information: Appeasement and European foreign policy of the Chamberlain ministry

France

France wanted to make friends against the danger from Germany, especially with Britain and smaller countries in Central Europe. In the 1920s, France helped in places like the Rhineland and supported Poland and Spain. The Maginot Line was built to stop attacks from Germany.

In the 1930s, France had money problems and political trouble. Appeasement became a policy as Germany got stronger, leading to things like the Munich Agreement of 1938. France also took control of arms makers and built up its army in the late 1930s.

Fascism

Fascism grew as a strong political movement in Europe after World War I, especially in Italy and Germany. It was known for strict nationalism, being against liberalism and Marxism, and using force to get what it wanted. Fascist countries like Italy and Germany made aggressive plans and formed groups that helped start World War II.

Germany

After World War I, Germany became a republic but had many problems inside and outside the country. The Treaty of Versailles made Germany pay a lot of money and lose land, causing hard times and political trouble. The Weimar Republic had trouble with fights from different groups.

In 1933, the Nazi Party took over, and Germany became a dictatorship under Adolf Hitler. Hitler made aggressive plans, taking land from other countries and finally invading Poland in 1939, which started World War II.

Eastern Europe

After World War I, new countries appeared in Eastern Europe as big empires broke apart. Countries like Poland, Czechoslovakia, and Yugoslavia were created, but they often had problems with different groups of people and political trouble. The Baltic states—Estonia, Latvia, and Lithuania—became free from Russia but were later taken over by the Soviet Union.

Soviet Union

The Soviet Union started after the Russian Revolution and faced attacks from other countries during the Russian Civil War. In the 1920s, it made trade deals and secretly let Germany train its army. Under Joseph Stalin, the Soviet Union followed a plan called "Socialism in One Country" and later joined forces against fascism with the "Popular Front."

In the late 1930s, the Soviet Union tried to make friends with Western countries but instead made a deal with Germany, sharing parts of Eastern Europe and sending supplies to Germany before it was attacked in 1941.

Spanish Civil War

The Spanish Civil War showed how Europe was split, with right-wing groups helped by fascist Italy and Nazi Germany fighting left-wing groups supported by the Soviet Union and volunteers from many countries. The war ended with the right-wing group winning under Francisco Franco, who ruled with strict rules and stayed out of World War II.

Main article: Fascism in Europe

Main article: Weimar Republic

United States

Main articles: History of U.S. foreign policy, 1913–1933 and Foreign policy of the Franklin D. Roosevelt administration

In the 1920s, the United States took part in world events. American leaders helped solve issues in Europe and Asia, even though the U.S. did not join the League of Nations. The country used its resources to support peace and help other nations heal after World War I.

American leaders aimed to reduce weapons, especially ships, to avoid future wars. They also worked to assist Germany in repaying money owed after the war, making the payments more manageable over time. The U.S. adjusted its approach to Latin America, promising not to interfere in other countries' matters.

Latin America

The United States changed its foreign policy with the Good Neighbor Policy. This meant the US would not interfere in Latin American countries anymore. American troops left places like Haiti. New agreements with Cuba and Panama ended special US control over them. In 1933, the Montevideo Convention was signed. This promised not to get involved in the internal matters of Latin American nations without their agreement. This helped Cuba become more independent.

The Great Depression in Latin America hurt many countries. The demand for their raw materials dropped sharply, especially in Chile, Peru, and Bolivia. Leaders in Latin America began to support import substitution industrialization. This meant building stronger economies with their own industries. Even though this sometimes threatened US business interests, President Roosevelt followed the Good Neighbor policy. He did not stop countries like Mexico from taking control of foreign companies, including oil companies, to build their own state-run Pemex.

Brazil

In Brazil, a revolution in 1930 ended the rule of coffee plantation owners. New leaders focused on industry and modernization. By 1933, new industries helped improve the economy. Brazil worked more closely with the United States. Later, during World War II, Brazil became a strong ally of the United States.

Border disputes and warfare

While many small border disagreements happened, only one grew into a major war: the Chaco War from 1932 to 1935. Bolivia and Paraguay fought over the Gran Chaco region, where oil was found. The war ended with a peace treaty giving most of the land to Paraguay.

Asia and Africa

Egypt

Main article: Kingdom of Egypt

In 1922, the United Kingdom said Egypt was free, but still kept control of important places like the Suez Canal and the army. Egypt’s King Fuad died in 1936, and King Farouk became king at just sixteen years old. Farouk later made a deal with Britain. British soldiers would leave Egypt by 1949, except for those at the Suez Canal.

Japan

Further information: Foreign relations of Meiji Japan, Second Sino-Japanese War, and Japan–Russia relations

At this time, Japan’s military became very strong and took control of the government. They used harsh policies, especially toward China. In 1931, Japanese leaders took over a part of China called Manchuria and made a new state called Manchukuo. This made Japan leave the League of Nations. Japan wanted to control much of Asia under what they called the “Greater East Asia Co-Prosperity Sphere.” The United States and other countries did not agree with Japan’s actions and put limits on them.

China

Main articles: History of the Republic of China and Warlord Era

After throwing out the last emperor in 1911, China had trouble with local leaders called warlords. A leader named Sun Yat-sen tried to unite the country but died in 1925. Chiang Kai-shek took over and started to bring parts of China together. In 1927, he turned against communist groups and chased them across the country during what is known as the Long March. Japan also attacked parts of China, causing big fights. Even with these problems, China got help from many countries, especially the United States and Britain.

India

Main articles: Imperial Conferences and League of Nations

India joined the talks that ended World War I and signed the Treaty of Versailles on its own, not just with the United Kingdom. This let India join the League of Nations in 1920. India also went to meetings of the British Empire to talk about things like trade and the rights of Indians living in other places. One big problem was how Indians were treated in South Africa, where laws were often unfair to them. India worked with South Africa to make things better, but there were still difficulties.

Coming of World War II

Main articles: Causes of World War II and Diplomatic history of World War II

Wars

• Turkish War of Independence
  • Greco-Turkish War (May 1919 – October 1922)
  • Turkish–Armenian War (September–December 1920)
  • Franco-Turkish War (December 1918 – October 1921)
  • Royalist and separatist revolts (1919–1923)
• Unification of Saudi Arabia
  • Rashidi-Saudi War (1903–1921)
  • Kuwait-Saudi War (1919–1920)
  • Hejaz-Saudi War (1919–1925)
  • Transjordan-Saudi War (1922–1924)
• Polish–Soviet War (February 1919 – March 1921)
• Irish War of Independence (January 1919 – July 1921)
• Iraqi revolt against the British (1920)
• Rif War (1920–1927)
• Pacification of Libya (1923–1932)