The World War II has been the largest armed conflict in history and the one involving the most nations. In a first phase, it was a European war, which became global after 1941.
It can be divided into two stages:
The invasion of Poland began in the early hours of September 1st, and ended on September 29th, 1939, with the fall of Warsaw. Poland was occupied by the German army. In accordance with the German-Soviet agreement of August of the same year, on September 17th Stalin sent the Red Army and occupied the eastern part of Poland. Germany and the USSR split up Poland. In addition, Germany gave its approval to the Soviet ambitions to occupy the territory of Latvia, Estonia, Lithuania and Bessarabia. In return, the USSR agreed to hand over war material to Hitler.
With the occupation of Poland, a period of indefinite war began, without major war operations, which was defined as the so called “drôle de guerre” (the phoney war). On the Allied side, Great Britain and France wanted to open a new peripheral front to force Germany to the negotiating table. For his part, Hitler intended to launch an offensive against France to bring Britain to the negotiating table.
Hitler's plans for a rapid occupation of France ran into two problems:
Hitler had to delay the occupation of France by up to 29 times between October 1939 and June 1940.
Division within the Allies, between what proposed by Great Britain (Prime Minister Churchill) and what the French government of Pétain. Churchill proposed an attack in the Baltic Sea through Norway to Sweden (which supplied Hitler with steel).
On November 30th, Stalin issued an ultimatum to Finland based on the agreements with Germany. Finland refused to make territorial concessions to the USSR and Stalin began the operations to occupy Finland on the same day, 30 November, known as the “Winter War.” The campaign for the occupation lasted one hundred and five days until March 12th, 1940 and ended with the occupation of Karelia, a part of Finland's territory.
Churchill's proposal to open a front in the Baltic Sea became more meaningful as a result of the occupation of Finland. Entering the military campaign alongside Finland required recognition of the Swedish and Norwegian governments. Their refusal left the option on standby, until the March 1940 armistice between the USSR and Finland disrupted the Allies' plans.
The French proposal consisted of a pressure operation in Germany, opening a front in the south, to attack the Caucasus oil fields. It was an attack on the USSR. It required advancing through Greece to the south of the USSR, but Italy's entry into the war was feared. This operation never took place.
Chamberlain, British Prime Minister until May 1940, prepared to send a military force to Finland, though Hitler went ahead. In April 1940, Germany invaded Norway. This was the first British disaster. Consequence: Chamberlain resigned.
After Germany's military advances in 1940, the new British Prime Minister, Winston Churchill, realized that there was no room for negotiation with Hitler.
Hitler's plan in 1940 was to invade rapidly both Belgium and the Netherlands. Churchill called this German operation a “sickle-coup movement,” because it was intended to divide the British military contingent in northern France from the bulk of the French army. The German army, once it had reached the sea, was to head towards France by drawing a curved line.
The German invasion of France, Belgium, the Netherlands, and Luxemburg began on May 10th, 1940, and marked the end of the Phoney War.
The operation was a success for Hitler. The rapid invasion allowed him to silence all the critics within the Reich's army.
France presented the surrender. On June 17th, Marshal Pétain announced that France would ask for an armistice. Pétain convened the National Assembly in Vichy and got a majority to approve the dissolution of the democratic Third Republic and its replacement by an authoritarian Republic. France was divided into different territories:
General de Gaulle, who was in London when France's surrender, refused to recognize the Vichy government as legitimate, and started the task of organizing the anti-fascist resistance under the name of Free France.
Hitler allowed the Vichy Republic to keep the African colonies under Pétain's control, on the condition that they would not be placed at the service of Britain.
For Churchill, the last salvation of France was to offer Pétain the formation of a Franco-British confederation with the integration of France into the British Empire. The proposal was rejected. Hitler proposed to Churchill to end war hostilities if Britain recognized Germany's hegemony in Europe. This never happened.
Germany invaded Nice and the Savoy with the occupation of France. This fact made Mussolini decide to enter the war. Germany wanted to avoid making war in the East any longer.
Churchill was not ready to make any negotiation with Germany. Churchill's actions against German-allied France were:
Meanwhile, Britain was beginning to prepare for a more than likely German invasion. In July-August 1940, Hitler carried out the “Operation Sea Lion” operation, which according to the Führer's plans was to be a lightning war from the air. Yet, Hitler did not have enough planes and the British government, which had begun rearming, was in a position to defend itself thanks to the radar. An intense battle of the air took place.
August-September: German aviation failed to defeat the British, and on October 12th Hitler suspended the operation. After the unsuccessful conclusion of the British occupation, Hitler began preparations to invade the Soviet Union, the so-called “Operation Barbarossa.”
Following the end of England's campaign, a new stage of impasse began. Diplomatic rallies were reactivated, and the war shifted to side scenarios in the Mediterranean.
Italy invaded Albania and Greece in October 1940. Britain had been left alone in Europe and was desperately seeking America's entry into the conflict. Against the British will, was the Republican Party, which rejected any commitment by the United States to the European war (they advocated maintaining the isolationist policy). President Roosevelt reactivated a clause in the Wartime Principles of Trade that allowed Britain and France to buy industrial equipment, provided it was paid for in cash. In 1940, Roosevelt was re-elected. Churchill and Roosevelt maintained a cordial relationship.
Throughout WWII, there was never a single allied command. The development of the war was based on maintaining good relations between Roosevelt, Churchill and Stalin. In March 1941, Roosevelt took office and went beyond the “Cash and Carry” clause by pushing for a loan law that allowed sales through the loan system. It was a first step in American support for England which had been left alone on the Allied side.
The Tripartite Pact, also called the Pact of the Axis Powers, was a cooperative military agreement signed in Berlin on September 27th, 1940, between Nazi Germany, the Kingdom of fascist Italy, and the Japanese Empire.
Italy used the pact to start its war in the Mediterranean. Hitler had to accept it.
Officially, at the end of 1940, it was planned to strengthen the alliance between Russia and Germany. The proposal was to create a continental pact of nations extending from Spain to the Middle East. In November 1940, Soviet Minister Molotov travelled to Berlin. But no agreement was reached. It was felt from the USSR that the war was getting too close to their borders. Stalin predicted that Germany had decided that its next target was Russia.
In 1941, the Communist International sent messages to the French and Belgian Communist Parties to begin to confront the German occupation through anti-fascist resistance movements.
In a mysterious plot, Rudolf Hess (second in the hierarchy of the Nazi party) parachuted over Scotland on May 10th, 1941, to try negotiating a deal with Churchill. Did Hitler know about this operation?
In May 1941, Operation Barbarossa, which had been unexpectedly delayed by Hitler, was ready. Initially, it had to be carried out in the Spring, as to reach Moscow as soon as possible, moreover before the harsh Winter. The Hitler plans could not be fulfilled. The Italians had become entrenched in Greece, and northern Libya was under attack by the French and the British. They needed the German aid.
Churchill attacked in the Mediterranean the weakest partner of the Axis, Italy. According to De Gaulle, Churchill initiated the Allied advance from southern Libya and Egypt, with Commander Montgomery at the helm, in January-February 1941. In April, the invasion of Italian occupied Greece began. But the Allied troops did not manage to win the battle.
Hitler had to postpone the attack on Russia to help Italy with troops from the Afrika Korps, and in Greece through Yugoslavia. Stalin interpreted it as the prologue of the occupation of Russia.
The delay of two months in the Barbarossa operation prevented the German army from occupying Moscow. The occupation of the USSR finally began on June 22nd, 1941.
German targets for Operation Barbarossa:
On December 5th, 1941, the German front stopped just 39 kilometres away from Moscow. Hitler had to order the withdrawal of its troops. First important setback of Germany in the war.
During Winter 1941, Stalin's army rebuilt its forces. But the siege of Leningrad had been a mass slaughter of the population.
After the invasion of Poland in 1939, the executions were selective and affected the Polish elite but not yet the Jews. With the invasion of the USSR in 1941, the mass execution of the population began. Hitler gave explicit instructions to proceed with the scorched earth tactic. They massacred the population that resisted and sent the Jewish population to the concentration camps. This was the beginning of the Holocaust.
On December 1st, 1941, the first stage of World War II came to an end. At this point it was not yet a world war.
On December 7th, 1941, Japan attacked the US naval base at Pearl Harbor. Hitler wanted Japan to attack the USSR from the east. But Japan did what Churchill wanted most, to attack the United States of America. The American attack and response turned the war, until then on European soil, into a world war.
Japan's reason had no military logic. The British historian A.J.P. Taylor believed that by this action, Japan wanted to prove its loyalty to Hitler.
President Roosevelt got the support of the US Senate to declare war on Japan. In December 1941, the new phase of the war strengthened Hitler's political determination.
In 1942, the Axis was advancing into the Pacific. Japan was pursuing a policy of rapid expansion:
The objects were to conquer Australia and New Zealand to drive out the British, advance on India, and create an Asian sphere of affluence under Japanese control.
On February 15th, 1942, Singapore was occupied. The Japanese navy sunk British warships in the Far East. This was the most important surrender of Britain during the entire war. Japan reached Burma and the jungles of New Guinea. There, the Japanese advance was halted. In Australia the Japanese could never reach it.
During Summer 1942, the Japanese advance was halted. Meanwhile, in Africa, German troops from the Afrika Korps were gaining ground.
Hitler's second offensive on the USSR began. It was no longer Stalin's surrender that was being sought, but the invasion of the Caucasus to control the oil fields. The Allies came to fear that the Japanese advance and the German offensive into the Caucasus might be directed at India.
The military fortunes of the war turned in favour of the Allies throughout 1942.
Chronology of the most outstanding events between 1942 and 1944:
The options Hitler put on the table to get out of the situation Germany was in, were to make use of a new military weapon: the Wunderwaffen (miracle weapons).
Chronology of the final events of the war, 1944 - May 1945:
First, the war with Germany in Europe ended. Then, the war moved to the Pacific with the fundamental decision of the use of the atomic bomb in the summer of 1945.
The conferences in Tehran, Yalta and Potsdam organized the post-war world into two antagonistic blocks.