World War II: Causes, Major Battles, Consequences and Legacy (1939-1945)

2nd World War (1939-45):

1925: The Locarno Pact was accepted by France, Germany and the allies, and the Treaty of Versailles was partially undermined. 1928: The Kellogg-Briand Pact condemned war. 1929: Germany stopped paying reparations and began rearming. Japan's imperialist policy and the weakness of the Western democracies and the League of Nations are key factors in the outbreak of war.

The Asian path to war: 1)

The invasion of China by Japan (1931) led to the creation of Manchukuo in Manchuria. Japan left the League of Nations. 1933: Japan withdrew from the League. The Meiji Restoration had already ended the shogunate.

2) Revisions of the Treaty of Versailles and Hitler's rise to power

1933: Germany abandoned the League of Nations. 1935: Compulsory military service was reintroduced. 1936: Germany remilitarized the Rhineland.

3) Italian fascism and the invasion of Ethiopia

Italy's fascist regime invaded Ethiopia. The Spanish Civil War (1936) saw Italian and German governments support the rebels against the Republic, which received support from the International Brigades and the USSR.

1936: Friendship pact between Germany and Italy: the Rome-Berlin Axis.

The Anti-Comintern Pact linked Germany, Japan and Italy against the USSR, forming the front that would lead to war.

1937: Japan and China fought a full-scale war.

Expansion of Germany

1. Annexation of Austria, against the Treaty of Versailles.
2. The annexation of the Sudetenland, agreed at the Munich Conference of 1938 (Italy, Germany, Great Britain and France).
3. 1939: Invasion of Czechoslovakia, which became two protectorates (Bohemia and Moravia), while Slovakia became a satellite state.

The first victories of the Axis: Poland

Poland was divided into two zones: the North and West were annexed by Germany, while the East went to the USSR. Denmark, Norway, France (1940) fell, and the Maginot Line was overcome to establish the German frontier. Attacks against the Netherlands, Luxembourg, Belgium and northern Italy followed. Marshal Pétain's government signed the armistice with Germany. France was divided into two zones: the North under German occupation and the South, under the Vichy regime.

From London, General de Gaulle called for resistance. The Battle of Britain: German bombings of England aimed at the civilian population, with the objective of causing panic and forcing Britain to negotiate.

In North Africa, the campaign against the British began, and the Afrika Korps under Rommel fought in Egypt.

In 1939, the situation was defined by: 1) the Pact of Steel between Italy and Germany; 2) the secret Molotov-Ribbentrop Pact with the USSR, which allowed Germany to attack Poland and avoid a war on two fronts. On 1 September 1939 Germany invaded Poland, and on 3 September France and Britain declared war.

Alliances

1. Axis: Germany, Italy, Japan, Hungary, Romania, Bulgaria and Slovakia.
2. Allies: Great Britain, France, the Soviet Union (after June 22, 1941, when Germany invaded the USSR), and later the United States.

Three fronts were established. Germany's initial strategy was a lightning war (Blitzkrieg), which succeeded in conquering large territories quickly, but the German advance eventually slowed. The first victories were followed by logistical problems and the resistance of the Soviets. The siege of Leningrad lasted for over 800,000 deaths. In the south, Germany aimed at Ukraine and the Caucasus, reaching Stalingrad. In the center, the Germans sought Moscow and came within 15 km of it, but winter and Soviet counterattacks forced the German Blue Plan to retreat.

Japan's intervention:

Japan was driven by imperialist expansion. In 1941 Japan attacked Pearl Harbor, bringing the United States into the Second World War on the side of the Allies. Japan advanced gradually across Southeast Asia, aiming to build a “Greater East Asia” under its control. From 1942, the initiative shifted to the United States, which won the Battle of Midway and the Battle of Guadalcanal. Japan then resorted to desperate measures, including kamikaze attacks.

Allied victories:

The winter of 1942-43 was decisive. The German Blue Plan in the USSR, aimed at the Caucasus oil fields, failed. In North Africa, after the Battle of El Alamein, Rommel was defeated by the British under Montgomery and forced to withdraw from Egypt. The Allies landed in Morocco and Algeria and advanced into Tunisia, gradually clearing North Africa. The Battle of Stalingrad was a turning point, halting the German advance into the Caucasus.

Defeat of the Axis:

In 1943 the Germans suffered a major defeat in the Battle of Kursk, the largest tank battle in history. This was the beginning of the German retreat on the Eastern Front. Mussolini's fascist regime collapsed, and Italy signed an armistice with the Allies. The Italian government then fought alongside the Allies, while northern Italy was under the Italian Social Republic (Salò Republic) controlled by Germany.

War Economy:

Economic intervention by the totalitarian states was extensive, while the economies of the United States, France and the United Kingdom continued to function under wartime production. The Second World War brought major technological innovations: computers, the evolution of aviation (aircraft, aircraft carriers, bombers, missiles), and the creation of the atomic bomb.

Extermination in the War:

The development of racist and totalitarian policies led to the idea of racial supremacy, racial purity and the extermination of those considered inferior. Racism was one of the most important ideological pillars of Nazism. Jews, along with other groups, were targeted for extermination. From 1941, Hitler ordered the systematic murder of Jews across occupied Europe. The Holocaust, the genocide of the Jewish population, was carried out in extermination camps such as Auschwitz, which became the most macabre symbol of the horrors of humanity. Mass killings of civilian populations also occurred on the Eastern Front, where millions of Soviet citizens were murdered. Bombings of cities were carried out by both sides, including the atomic bombings of Hiroshima and Nagasaki by the Allies.

Collaboration and Resistance:

During the German occupation, a considerable proportion of the population in occupied countries supported Nazi ideas and offered their help to the German administration. Those who collaborated were called collaborationists: 1) collaborationist groups supported Nazi ideology in occupied countries; 2) the resistance fought against occupation and Nazism. Resistance movements were strongest in France, Italy, Yugoslavia and the USSR, often led by communist partisans.

Consequences of the war:

1. Demographics: Some 50 million people died, including about 21 million in the USSR and 6 million Jews in the Holocaust. Most deaths were caused by combat, bombings and violence. Eastern Europe suffered most. Forced displacements, forced labor, and concentration camps affected some 20 million people, leaving many disoriented and creating the conditions for future conflict.
2. Territories: Borders shifted, with the USSR moving its frontier west. The Baltic states and parts of Eastern Europe came under Soviet control, while Poland was moved westward, and millions of Germans and Poles were displaced. Japan lost its imperial territories. Austria regained its independence. Yugoslavia was reorganized. Italy lost territories.
3. Economics: Europe was in ruins (industry, transport, cities). Reconstruction was led by the United States through the Marshall Plan in Western Europe, while the USSR took control of Eastern Europe.

After the war, Germany was divided into four zones, eventually into two states: the German Democratic Republic (East) and the Federal Republic of Germany (West), aligned with the Soviet and Western blocs respectively. Berlin was also divided among the four powers.

4) The United Nations

The United Nations (UN) was founded in October 1945 to solve international problems and maintain peace. Its headquarters is in New York. It includes the Security Council and the International Court of Justice in The Hague, whose fundamental purpose is to maintain world peace.