Second World War: Origins, Key Events, and Legacy

Posted on Mar 15, 2025 in History

Causes and Sides of the Second World War

Causes of the War

The main causes of the war were:

Dissatisfaction with the peace treaties: Germany lost about 15% of its territory after the Treaty of Versailles, while Italy only received a portion of the territories promised. This caused resentment.
Consequences of the Great Depression: States adopted protectionist economic policies (reducing imports) to combat unemployment. This led to rivalry between countries, and totalitarian regimes tried to solve these problems by implementing economic policies based on the arms industry and conquering lands for markets and resources.
Expansion of totalitarian regimes: Germany, Italy, Japan, and later the USSR, initiated an expansionist policy:
1. Germany aimed to create a large, ethnically pure German state, including ethnic German populations and lands with economic potential: Austria, Czechoslovakia, and Poland.
2. Italy conquered Ethiopia and Albania.
3. Japan sought to become the main power in the Far East, occupying China.
4. The USSR aimed to control Finland, Estonia, Latvia, Lithuania, and Poland.
Appeasement policies: France and the United Kingdom tolerated totalitarian expansion to avoid another war, also viewing communism as a greater threat than fascism and Nazism. The United States remained neutral.
Ineffectiveness of the League of Nations (SDN): The SDN was incapable of preventing totalitarian regimes from their expansionist policies because it lacked the means to enforce economic and diplomatic sanctions.

Formation of Opposing Sides

International tension led to the creation of various alliances:

The Axis: Consisted of the totalitarian states of Germany, Italy, and Japan. In 1936, Germany and Italy signed an alliance, the Rome-Berlin Axis. Also in 1936, Germany and Japan signed the Anti-Comintern Pact, and Italy joined in 1937. In 1939, Germany signed the Molotov-Ribbentrop Pact with the USSR, promising not to attack each other and to divide Poland.
The Allies: Led by the United Kingdom, France, the USSR, and the United States. In 1939, Germany and the United Kingdom signed a support pact, and shortly after, a defense agreement with Poland. In 1941, the USSR joined the Allies after being attacked by Germany, and the United States joined after being attacked by Japan.

Development of the War: Axis Advances

Between 1939 and 1941, the Axis controlled most of Europe, North Africa, the Middle East, the Far East, and the Pacific.

German Military Superiority

During the first years of the war, Germany enjoyed military superiority due to:

Investment in the arms industry, resulting in numerous and technologically superior air and land forces.
A new tactic, the Blitzkrieg (lightning war), a strategy involving aerial bombing by the Luftwaffe followed by rapid surprise attacks by land forces.

The African Front

Italy opened a new front in Africa. The United Kingdom needed the Suez Canal to maintain contact with India and Australia, while the Axis wanted it to gain access to the oil of the Middle East. In 1940, Italy attacked Egypt but was defeated. Germany sent the Afrika Korps, led by Rommel, which regained the lost territories.

German Expansionism

September 1939: Germany invaded Poland, conquering it in less than a month and sharing it with the USSR. The USSR also occupied the Baltic states and Finland.
1940: Germany invaded Denmark and Norway to access Swedish steel and threaten the United Kingdom with its planes.
May 1940: The Germans attacked the western front, occupying Belgium, Holland, and Luxembourg. The British, surrounded in Dunkirk, retreated, leaving the French.
Then, Italy attacked France, and on June 22, the French government surrendered, signing the Compiègne armistice. France was divided between the North, occupied by the Nazis, and a puppet government in the South, Vichy France.
July 1940: Hitler began an aerial campaign to destroy the RAF (Royal Air Force) and demoralize the English population by bombing British cities, aiming to invade the United Kingdom (Operation Sea Lion). However, due to the British use of radar and the RAF, the campaign ceased in July 1941.
April-June 1941: Hitler invaded Greece and Yugoslavia, and obtained the alliance of Hungary, Romania, and Bulgaria, controlling almost all of Europe.

Entrance of the USSR and the United States

On June 22, 1941, Germany invaded the USSR (Operation Barbarossa), aiming to occupy Moscow, Kiev, and Leningrad, taking control of Ukrainian wheat and Caucasian oil. Stalin joined the Allies and adopted a scorched earth policy: retreating after destroying anything the enemy could use. Hitler anticipated a quick victory, but the German army was stopped near Moscow due to lack of winter clothes and extreme cold. Japan invaded Indochina, and the United States tried to prevent its expansion with an embargo on steel and oil exports to Japan. Japan responded by partially destroying the US fleet in the Pacific at Pearl Harbor (December 1941), and the United States joined the Allies.

The Allies’ Response

The Allies’ Counteroffensive

In the USSR: The Germans still held the siege of Leningrad but were forced to retreat in Moscow. In 1942, the Germans attacked Stalingrad, but after months of street-by-street fighting, they surrendered in February 1943. The Soviets then recovered Crimea, Ukraine, and broke the siege of Leningrad.
In Africa: In 1942, the Afrika Korps advanced towards Cairo but, due to lack of supplies, were defeated by the British at El Alamein. Simultaneously, the Anglo-Americans arrived in Morocco and Algeria, and in May 1943, the Axis forces were expelled from Africa by the Allies.
Sicily: From North Africa, the Allies landed in Sicily and occupied it. King Victor Emmanuel III ordered Mussolini’s arrest, and in September, Italy signed an armistice with the Allies.
Battle of the Atlantic: The Germans used U-boats (submarines) to prevent supplies from reaching the Allied armies. In response, the Allies used aircraft carriers and destroyers to attack the U-boats.
Asia: Japan tried to conquer Midway to attack Hawaii and destroy the American fleet in April 1942. In the Battle of Midway, the US defeated the Japanese navy, demonstrating their military superiority in the Pacific.
Cooperation among the Allies: In November 1943, at the Conference of Tehran, the leaders of the USSR (Stalin), the US (Roosevelt), and the UK (Churchill) devised a strategy to defeat Germany.

The Defeat of the Axis

Italy: After the armistice, Germany invaded northern Italy, freed Mussolini, and made him head of a new state: the Italian Social Republic. The Allies and the Italian resistance forced the Germans to retreat and defeated them at Monte Cassino. Mussolini tried to flee but was captured and executed, and the Germans retreated to the Alps.
In the West: In June 1944, the Allies landed in Normandy (Normandy Landings), and Paris was liberated in August. By November, France and Belgium were liberated, and the Allied army entered Germany from the southwest.
In the East: The Red Army expelled the Germans from Poland, Hungary, and Czechoslovakia and entered Germany from the East.
Invasion of Germany, late 1944 – early 1945: Hitler refused to surrender and mobilized the entire population. Nevertheless, in April 1945, the Soviets entered Berlin, and Hitler committed suicide on May 2. On May 8, Germany signed its unconditional surrender.
End of the war in the Far East: By January 1945, the US Navy had recovered all Pacific islands conquered by the Japanese and captured Iwo Jima, advancing towards the Japanese archipelago. Japan was surrounded but refused to surrender. In August 1945, US President Harry Truman authorized the dropping of atomic bombs on Hiroshima and Nagasaki, and the Soviets invaded Manchuria. Japan surrendered on September 2, 1945.

Economy and Society During the War

War Economy

The Second World War was a total war. All countries established a wartime economy based on:

Overexploitation of natural resources: Warring countries needed food, raw materials (iron, nickel, rubber), and energy sources (coal, oil). The Axis countries exploited the resources of conquered countries. The Allies relied on their colonies and the United States.
Development of heavy industry: Countries prioritized heavy industry (steel and chemical) over the production of consumer goods.
Forced labor: The Axis exploited the people of conquered territories. The USSR used prisoners of the gulags in arms production.
Arms industry: Economic development centered on the arms industry, especially offensive weapons like tanks and planes.

Suffering of the Civilian Population

Total war severely affected the civilian population:

Rationing of basic commodities (food, clothing, fuel), and a black market appeared.
Systematic bombing of cities and civilian targets, resulting in severe economic and human losses.
Use of propaganda to promote patriotism and hatred of the enemy. The Allies defended democratic values, while the Axis defended their racial superiority and the rejection of Jews and communists.
Systematic violence in countries occupied by Germany and Japan, using ethnic and political motives as justification.
Appearance of collaborators, people who supported the Germans, and the Resistance, a clandestine opposition to the Axis in occupied territories, cooperating with the Allies through sabotage, espionage, or military attacks.

Consequences of the Second World War

Demographic Consequences

There were more civilian than military deaths during the war. Sixty million people died, 35 million were wounded, and another 35 million were displaced or deported. The most affected countries were the USSR, China, Germany, Poland, and Japan.

Territorial Changes

The USSR received eastern Poland, Romania, Finland, Estonia, Lithuania, and Latvia.
Poland received part of Eastern Germany and half of Eastern Prussia.
Italy lost its African colonies and Trieste.
Germany and Austria were divided into zones controlled by the Allies.

Economic Consequences

Battles in Europe, Asia, and Africa destroyed farmland, cities, factories, and basic infrastructure (ports, airports, roads).
Europe lost about 50% of its industry.
The United States became the leading global power due to its agricultural and industrial production and financial capacity.
The USSR became the second industrial power, despite its human losses, due to the industrialization of the Urals and the seizure of German factories.
Other countries, such as Canada, Australia, and Sweden, experienced industrial economic growth.

The Peace Settlement

Peace Conferences

The Allies reached agreements about the post-war settlement at several conferences:

Tehran Conference (1943): Stalin, Churchill, and Roosevelt agreed to launch a joint attack against the Axis powers.
Yalta Conference (February 1945): Agreements were reached about post-war Germany: democratic elections in liberated territories, disarmament, denazification, and division of Germany and Austria into four zones controlled by the United States, the USSR, the United Kingdom, and France. The USSR would annex the Baltic states and Eastern Poland, and Poland would receive part of Eastern Germany. A new international organization would ensure international peace and security.
Potsdam Conference (August 1945): With the United States (Truman), the United Kingdom (Attlee), and the USSR (Stalin), it was decided to ratify the Yalta agreement, try Nazi war criminals at an international court, and control Japan by the United States.

Creation of the United Nations

At the San Francisco Conference (June 1945), the United Nations was founded to replace the League of Nations. The main goals of the UN were to maintain international peace and security, respect people’s right to self-determination, protect human rights, and promote peaceful cooperation. Furthermore, the Universal Declaration of Human Rights (1948) was passed.

The Nuremberg and Tokyo Trials

The Nuremberg trials took place between November 1945 and October 1946. Six hundred members of the Nazi Party, government, army, and police were arrested and accused of:

Crimes against peace: causing a war.
War crimes: murder and execution of prisoners of war, destruction of cities, etc.
Crimes against humanity: genocide, enslavement, deportation, and persecution for political, racial, or religious motives.

There were various trials: the main trial against the top figures in the Nazi regime, against doctors, against judges, etc.

Tokyo trials were held between 1946 and 1948 against Japanese state and high-ranking military figures accused of similar crimes to the Nazis.

Glossary

Appeasement: The foreign policy of democratic regimes that allowed the expansionism of totalitarian regimes to avoid war.
Axis: One of the sides that fought in the Second World War, including the totalitarian regimes of Germany, Italy, and Japan.
Allies: The side that fought against the Axis during the Second World War, led by France, the United Kingdom, the USSR, and the United States.
Collaborators: Civilians in occupied territories who supported the Axis for economic or ideological reasons.
Blitzkrieg: A new strategy involving aerial bombing by the Luftwaffe followed by rapid surprise attacks by land forces.
Resistance: The clandestine opposition to the Axis in occupied territories that cooperated with the Allies.
Holocaust: The organized and systematic mass assassination of nearly 6 million Jews by the Nazi regime and their collaborators in occupied territories during WWII.
Wannsee Conference: A meeting in 1942 where the Nazis decided on the mass organized transport of Jews to concentration camps (slave labor) or extermination camps.
UN (United Nations Organization): An international organization created to replace the League of Nations, with the goals of maintaining international peace and security, respecting people’s right to self-determination, protecting human rights, and promoting peaceful cooperation.

Chronology

September 1, 1939: Invasion of Poland. Start of the war.
1940: Invasion of Norway and Denmark. Invasion of Luxembourg, the Netherlands, and Belgium. Armistice of Compiègne. Surrender of France.
June 22, 1941: Operation Barbarossa. Invasion of the USSR.
December 7, 1941: Pearl Harbor. The United States enters the war.
1942: Battle of El Alamein. Axis defeat in Africa. Midway. Japanese defeat in the Pacific.
1943: End of the Battle of Stalingrad. Germany begins to retreat in the USSR. Sicily. September: Surrender of Italy.
June 1944: Normandy landing. Second front in Europe.
May 9, 1945: Germany surrenders.
September 2, 1945: Japan surrenders.