World War II

World War II (abbreviated WWII), or the Second World War, was a worldwide conflict fought between the Allied Powers and the Axis Powers from 1939 until 1945. Armed forces from over seventy nations engaged in aerial, naval and ground-based combat. Spanning much of the globe, World War II resulted in the deaths of over 72 million people, making it the deadliest conflict in human history. The war ended with an Allied victory.

Overview

War in Europe

Main article: European Theatre of World War II

On September 1, 1939, Germany, led by Adolf Hitler and the Nazi Party, invaded Poland according to a secret agreement with the Soviet Union.

On September 3 at 11:15 GMT, the United Kingdom, Australia, New Zealand, followed six hours later by France, responded by declaring war on Germany, initiating a widespread naval war. South Africa (September 6) and Canada (September 10) followed suit.

The Soviet Union joined the invasion of Poland on September 17.

Germany rapidly overran Poland, then Norway, the Netherlands, Belgium and France in 1940, and Yugoslavia and Greece in 1941. Italian and later German troops attacked British forces in North Africa. By summer of 1941, Germany had conquered France and most of Western Europe, but it failed to subdue the United Kingdom thanks to the resistance of the Royal Air Force and Royal Navy.

Adolf Hitler then turned on the Soviet Union, launching a surprise attack (codenamed Operation Barbarossa) on June 22, 1941. Despite enormous gains, the invasion stalled on the outskirts of Moscow in late 1941, as the winter weather made further advances difficult. The Germans initiated another major offensive the following summer, but the attack bogged down in vicious urban fighting in Stalingrad. The Soviets later launched a massive encircling counterattack to force the surrender of the German Sixth Army at the Battle of Stalingrad (1942–43), decisively defeated the Axis at the Battle of Kursk, and broke the Siege of Leningrad. The Red Army then pursued the retreating Wehrmacht to Berlin, and won the street-by-street Battle of Berlin, as Hitler committed suicide in his underground bunker on April 30, 1945.

Meanwhile, the Western Allies successfully defended North Africa (1940–43), invaded Italy (1943), and then liberated France (1944), following amphibious landings in Normandy. After repulsing a German counterattack at the Battle of the Bulge that December, the Western Allies crossed the Rhine River to link up with their Soviet counterparts at the Elbe River in central Germany.

During the war in Europe, some 6 million Jews, along with another 5 to 6 million people — Roma (Gypsies), Slavs, Communists, homosexuals, the disabled and several other groups — were murdered by Germany in a state-sponsored genocide that came to be known as The Holocaust.

War in Asia and the Pacific

Main article: Pacific War

The Empire of Japan invaded China on July 7, 1937. Australia and then the United States, in 1940, responded with embargoes on iron exports to Japan. On September 27, 1940 Japan signed the Tripartite Pact with Germany and Italy. After fruitless negotiations with the United States concerning withdrawal from China, excluding Manchukuo, Japan attacked Vichy French-controlled Indochina on July 24, 1941. This caused the United States, United Kingdom and Netherlands to block Japan's access to oil, such as that in the Dutch East Indies and British colonies in Borneo.

Japan launched nearly simultaneous surprise attacks against the major U. S. Navy base at Pearl Harbor, on Thailand and on the British territories of Malaya and Hong Kong. Though it was significant to the US Navy, most Americans had never heard of Pearl Harbor. The attacks occurred on December 7, 1941 in western international time zones and on December 8 in the east. Later on December 8, Japan attacked The Philippines, which was politically controlled by the United States at the time and quickly fell to Japanese forces. On December 11, Germany and Italy also declared war on the United States. Japanese forces commenced assaults on British and Dutch territory in Borneo on December 15. From their major prewar base at Truk in the South Pacific, Japanese forces began to attack and occupy neighboring Allied territories.

Japan's campaign in China lasted from 1937 to the end of the war, during which the Republic of China faced 80% of Japanese troops and relieved the Soviet Union under Stalin from fighting a two-front war. In the war against Japan, China lost more than 3 million soldiers and more than 17 million civilians. Many others were tortured, forced into slavery or raped, which resulted in charges of Japanese war crimes.

Japan won victory after victory in South East Asia and the Pacific, including the capture of 130,000 Allied prisoners in Malaya and at the fall of Singapore on February 15, 1942. Much of Burma, the Netherlands East Indies, the Australian Territory of New Guinea, and the British Solomon Islands also fell to Japanese forces.

The Japanese advance was checked at the Battle of the Coral Sea and their invasion fleet turned away from New Guinea after Allied naval forces clashed in the first battle in which the opposing fleets never made visual contact. A month later a Japanese invasion fleet was decisively defeated at the Battle of Midway in which they lost four fleet aircraft carriers attempting to engage U.S. Navy forces (the U.S. Navy lost one carrier). On land they were defeated at the Battle of Milne Bay, were pushed out of Papua New Guinea by predominantly Australian forces through the Kokoda Trail and finally withdrew from Battle of Guadalcanal as the Allies took the initiative in the Solomon Islands and began an "Island Hopping" campaign to push back Japanese holdings in the Pacific. U.S. and Australian forces then isolated Japan's major base at Rabaul before advancing from one island to another in the Central Pacific invading some and isolating others. The Japanese were defeated in a series of great naval battles, at the Battle of the Philippine Sea and the Battle of Leyte Gulf in 1944 in which the Allies further advanced towards the Japanese homeland by invading the Marianas and then the Philippines, setting up bases from which Japan could be bombed by strategic bombers like the B-29. 1945 saw invasions of key islands such as Iwo Jima and Okinawa. In the meantime, Allied submarines gradually cut off the supply of oil and other raw materials to Japan.

In the last year of the war US air forces conducted a strategic firebombing campaign against the Japanese homeland. On August 6, 1945, the U.S. dropped an atomic bomb on the Japanese city of Hiroshima, and on August 9 another was dropped on Nagasaki. On the same day the Soviets joined the Pacific campaign in Manchuria, quickly defeating the Japanese Kwantung Army there. Japan surrendered on August 14, 1945.

Aftermath

About 62 million people, or 2.5% of the world population, died in the war, though estimates vary widely (see World War II casualties). Large swaths of Europe and Asia were devastated and took years to recover. The war had political, sociological and economic repercussions that persist to this day.

Causes

Main articles: Causes of World War II, Events preceding World War II in Europe, and Events preceding World War II in Asia

The immediate causes of World War II are generally held to be the German invasion of Poland, as well as the Japanese attacks on China, the United States, and the British and Dutch colonies. All of the attacks resulted from the leadership of authoritarian ruling elites in Germany and Japan. World War II began after these acts of aggression were met with an official declaration of war or armed resistance.

Cause of war in Europe

Germany and France had been struggling for dominance in Continental Europe for fifty years, and fought two previous wars, the Franco-Prussian War, and World War I. Meanwhile the power of the Soviet Union threatened to eclipse them both as industrialization spread to this massive country. World War I had been a preemptive war by Germany against the precursor to the Soviet Union, the Russian Empire,^[1] but it ended in catastrophe for the Germans, with millions dead, the loss of some peripheral territory, and economic hardships.

In the six years preceding World War II, Adolf Hitler, leading the Nazi Party, took power in Germany and eliminated its democratic government, the Weimar Republic. As stated in Mein Kampf, an autobiographical book outlining his plans for the future, Hitler's goal was to invade and conquer lands around Germany, and to make them German. He railed against Communists and ethnic minorities, such as Jews. After taking power, he prepared Germany for another war with large political rallies and speeches.

During the late 1930s Hitler abrogated the Treaty of Versailles, which had brought peace after WWI. He remilitarized the Rhineland, and increased the size of the German army, navy, and air force.

The British and French governments followed a policy of appeasement in order to avoid a new European war, out of concern for perceived war-weariness of their populations due to the huge death tolls of the first World War. This policy culminated in the Munich Agreement in 1938, in which the seemingly inevitable outbreak of the war was averted when the United Kingdom and France agreed to Germany's annexation and immediate occupation of the German-speaking regions of Czechoslovakia. In exchange for this, Hitler gave his word that Germany would make no further territorial claims in Europe.^[2][3] Chamberlain declared that the agreement represented "peace for our time." In March 1939, Germany invaded the rest of Czechoslovakia, effectively killing any notions of appeasement.

The failure of the Munich Agreement showed that negotiations with Hitler could not be trusted, as his aspirations for dominance in Europe went beyond anything that the United Kingdom and France would tolerate. Poland and France pledged on May 19, 1939 to provide each other with military assistance in the event either was attacked. The British had already offered support to Poland in March.

On August 23, 1939, Germany and the Soviet Union signed the Molotov-Ribbentrop Pact. The Pact included a secret protocol that would divide Central Europe into German and Soviet areas of interest, including a provision to partition Poland. Each country agreed to allow the other a free hand in its area of influence, including military occupation. The deal provided for sales of oil and food from the Soviets to Germany, thus reducing the danger of a British blockade such as the one that had nearly starved Germany in World War I. Hitler was then ready to go to war with Poland and, if necessary, with the United Kingdom and France. He claimed there were German grievances relating to the issues of the Free City of Danzig and the Polish Corridor, but he planned to conquer all Polish territory to incorporate it into the German Reich. The signing of a new alliance between the United Kingdom and Poland on August 25 did not significantly alter his plans.

On September 1, 1939, Germany invaded Poland, causing France and the United Kingdom to declare war. The United Kingdom brought with it the huge British Empire, and most members of the British Commonwealth joined the war soon after.

Cause of war in Asia

Imperial Japan in the 1930s was largely ruled by a militarist clique of Army and Navy leaders intending to make Japan a great colonial power. Japan invaded Manchuria in 1931 and China in 1937 to bolster its meager stock of natural resources, to relieve Japan from population pressures and to extend its colonial realm to a wider area. The United States and the United Kingdom reacted by making loans to China, providing covert military assistance, pilots and fighter aircraft to the Chinese Kuomintang and instituting progressively broad natural resource embargoes against Japan. The embargoes could have ultimately forced Japan to give up its newly conquered possessions in China or find new sources of oil and other resources.

Japan was faced with the choice of withdrawing from China, negotiating some compromise, developing new sources of supply, buying what they needed somewhere else, or going to war to conquer the territories that contained oil, bauxite and other resources in the Dutch East Indies, Malay and the Philippines. Japan's leaders believed that the French, Dutch, Soviet and British governments were preoccupied with the war in Europe, and that the United States could not be war-ready for years and would compromise before waging full-scale war. Japan thus proceeded with its plans for the war in the Pacific, and invaded and conquered nations and colonial possessions throughout Asia and the Pacific.^[4]

For propaganda purposes, Japan's leaders stated that the goal of its military campaigns was to create the Greater East Asia Co-Prosperity Sphere. This, they claimed, would be a co-operative league of Asian nations, freed by Japan from European imperialist domination, and liberated to achieve autonomy and self-determination. In practice, occupied countries and peoples were completely subordinate to Japanese authority.

The direct cause of the United States' entry into the war with Japan was the attack on Pearl Harbor on December 7, 1941. Germany declared war on the United States on December 11, 1941.

Chronology

See also: Timeline of World War II

War breaks out in Asia (July 1937 – September 1939)

Main articles: Second Sino-Japanese War, Battle of Lake Khasan, and Battle of Khalkhin Gol

The Second Sino-Japanese War began in 1937, when Japan attacked deep into China from its foothold in Manchuria (Northeast China). On July 7, 1937, Japan, after occupying Manchuria since 1931, launched another attack against China near Beijing. The Japanese made initial advances but were stalled in the Battle of Shanghai. The city eventually fell to the Japanese in December 1937, and the capital city Nanjing also fell. As a result, the Chinese Nationalist government moved its seat to Chongqing for the remainder of the war. The Japanese forces committed brutal atrocities against civilians and prisoners of war in the Rape of Nanking, slaughtering as many as 300,000 civilians within a month. Neither Japan or China officially declared war, for a similar reason—fearing declaration of war would alienate Europe and the United States.

In Spring 1939, Soviet and Japanese forces clashed in Mongolia. The growing Japanese presence in the Far East was seen as a major strategic threat by the Soviet Union, and Soviet fear of having to fight a two front war was a primary reason for the Molotov-Ribbentrop Pact with the Nazis (other historians mention Munich Agreement as a supposition to this pact). The Japanese invasion of Mongolia was repulsed by Soviet units under General Georgiy Zhukov. Following this battle, the Soviet Union and Japan were at peace until 1945. Japan looked south to expand its empire, leading to conflict with the United States over the Philippines and control of shipping lanes to the Dutch East Indies. The Soviet Union focused on the west, leaving only minimal troops to guard the frontier with Japan.

War breaks out in Europe (September 1939 – May 1940)

Main articles: Invasion of Poland (1939), Winter War, Norwegian Campaign, and Occupation of Baltic Republics

On September 1, 1939, Germany invaded Poland, using the false pretext of a faked "Polish attack" on a German border post. The United Kingdom and France gave Germany two days to withdraw from Poland. Once the deadline passed on September 3, the United Kingdom, Australia, and New Zealand declared war on Germany, followed quickly by France, South Africa, Canada and Nepal.

The French mobilized slowly and then mounted only a token offensive in the Saar, which they soon abandoned, while the British could not take any direct action in support of the Poles in the time available (see Western betrayal). Meanwhile, on September 8, the Germans reached Warsaw, having slashed through the Polish defenses.

On September 17, the Soviet Union, pursuant to its secret agreement with Germany, invaded Poland from the east, throwing Polish defenses into chaos by opening the second front. A day later, both the Polish president and commander-in-chief fled to Romania. On October 1, hostile forces, after a one-month siege of Warsaw, entered the city. The last Polish units surrendered on October 6. Poland, however, never officially surrendered to the Germans. Some Polish troops evacuated to neighboring countries. In the aftermath of the September Campaign, occupied Poland managed to create a powerful resistance movement and contributed significant military forces to the Allies for the duration of World War II.

After Poland fell, Germany paused to regroup during the winter of 1939–1940 until April 1940, while the British and French stayed on the defensive. The period was referred to by journalists as “the Phony War” or the “Sitzkrieg” because so little ground combat took place. During this period Soviet Union attacked Finland on November 30, 1939, which started the Winter War. Despite outnumbering Finnish troops by 4 to 1, the Red Army found the attack embarrassingly difficult, and the Finnish defence prevented an all-out invasion. Finally, however, the Soviets prevailed and the peace treaty saw Finland cede strategically important border areas near Leningrad.

Germany invaded Denmark and Norway on April 9, 1940, in Operation Weserübung. Denmark did not resist, but Norway fought back. The Norwegian defense was undermined by the collaboration of Vidkun Quisling, whose name is now synonymous with "traitor". The United Kingdom, whose own invasion was ready to launch, landed in the north. By late June, the Allies were defeated and withdrew, Germany controlled most of Norway, and the Norwegian Army had surrendered, while the Norwegian Royal Family escaped to London. Germany used Norway as a base for air and naval attacks on Arctic convoys headed to the Soviet Union. Norwegian partisans would continue to fight against the German occupation throughout the war.

The Western Front (May 1940 – September 1940)

Main articles: Battle of France and Battle of Britain

The Germans ended the Phony War on May 10, 1940 when they invaded Luxembourg, Belgium, the Netherlands, and France. The Netherlands was quickly overwhelmed and the Dutch city of Rotterdam was destroyed in a bombing raid. The British Expeditionary Force (BEF) and the French Army advanced into northern Belgium and planned to fight a mobile war in the north, while maintaining a static continuous front along the Maginot Line further south. The Allied plans were immediately smashed by the most classic example in history of Blitzkrieg.

In the first phase of the invasion, Fall Gelb, the Wehrmacht's Panzergruppe von Kleist, raced through the Ardennes, a heavily forested region which the Allies had thought impenetrable for a modern, mechanized army. The Germans broke the French line at Sedan, held by reservists rather than first-line troops, then drove west across northern France to the English Channel, splitting the Allies in two.

The BEF and French forces, encircled in the north, were evacuated from Dunkirk in Operation Dynamo. The operation was one of the biggest military evacuations in history, as 338,000 British and French troops were transported across the English Channel on warships and civilian boats.

On June 10, Italy joined the war, attacking France in the south. German forces then continued the conquest of France with Fall Rot (Case Red). France signed an armistice with Germany on June 22 1940, leading to the direct German occupation of Paris and two-thirds of France, and the establishment of a German puppet state headquartered in southeastern France known as Vichy France.

Germany had begun preparations in the summer of 1940 to invade the United Kingdom in Operation Sea Lion. Most of the British Army's heavy weapons and supplies had been lost at Dunkirk. The Germans had no hope of overpowering the Royal Navy, but they did think they had a chance of success, if they could gain air superiority. To do that, they first had to deal with the Royal Air Force (RAF). The ensuing contest in the late Summer of 1940 between the two air forces became known as the Battle of Britain. The Luftwaffe initially targeted RAF Fighter Command aerodromes and radar stations. Hitler, angered by retaliatory bombing raids on Berlin, switched his attentions towards the bombing of London, in an operation known as The Blitz. The Luftwaffe was eventually beaten back by Hurricanes and Spitfires, while the Royal Navy remained in control of the English Channel. Thus, the invasion plans were postponed indefinitely.

After France had fallen in 1940, the United Kingdom was out of money. Franklin Roosevelt persuaded the U.S. Congress to pass the Lend-Lease act on March 11 1941, which provided the United Kingdom and 37 other countries with US$50 billion dollars in military equipment and other supplies, US$31.4 billion of it going to the United Kingdom and the Commonwealth. Canada operated a similar program that sent $4.7 billion in supplies to the United Kingdom.

The Mediterranean (April 1940 – May 1943)

Main articles: Balkan Campaign, Battle of the Mediterranean, North African campaign, and Yugoslavian Front (WWII)

Control of Southern Europe, the Mediterranean Sea and North Africa was important because the British Empire depended on shipping through the Suez Canal. If the canal fell into Axis hands or if the Royal Navy lost control of the Mediterranean, then transport between the United Kingdom, India, and Australia would have to go around the Cape of Good Hope, an increase of several thousand miles.

Following the French surrender, the British attacked the French Navy anchored in North Africa in July 1940, out of fear that it might fall into German hands. This contributed to a souring of British-French relations for the next few years. With the French fleet destroyed, the Royal Navy battled the Italian fleet for supremacy in the Mediterranean from their strong bases at Gibraltar, Malta, and Alexandria, Egypt.

Italy invaded Greece on October 28, 1940, from Italian occupied Albania, but was quickly repulsed. By mid-December, the Greek army advanced into southern Albania, tying down 530,000 Italian troops. Meanwhile, in fulfillment of Britain's guarantee to Greece the Royal Navy struck the Italian fleet on November 11, 1940. Torpedo bombers from British aircraft carriers attacked the Italian fleet in the southern port of Taranto. One battleship was sunk and several other ships were put temporarily out of action. The success of aerial torpedoes at Taranto was noted with interest by Japan's naval chief, Yamamoto, who was considering ways of neutralizing the U.S. Pacific Fleet. Mainland Greece eventually fell to a German invasion from the East, through Bulgaria.

Italian troops crossed into Egypt from Libya to attack British bases in September 1940, thus beginning the North African Campaign. The aim was to capture the Suez Canal. British, Indian and Australian forces counterattacked in Operation Compass, which stopped in 1941 after numerous Australian and New Zealand (ANZAC) forces were transferred to Greece to defend it from German attack. German forces (known later as the Afrika Korps) under General Erwin Rommel landed in Libya in February 1941 to renew the assault on Egypt.

Germany also invaded Crete, significant for the large-scale use of German paratroopers. Crete was defended by about 11,000 Greek and 28,000 ANZAC troops, who had just escaped Greece without their artillery or vehicles. The Germans attacked the three main airfields of the island of Maleme, Rethimnon, and Heraklion. After one day of fighting, none of the objectives were reached and the Germans had suffered appalling casualties. German plans were in disarray and the German commander, General Kurt Student, was contemplating suicide. During the next day, through miscommunication and failure of Allied commanders to comprehend the situation, Maleme airfield in western Crete fell to the Germans. The loss of Maleme enabled the Germans to fly in heavy reinforcements and overwhelm the Allied forces on the island. In light of the heavy casualties suffered by the parachutists, however, Hitler forbade further airborne operations.

In North Africa, Rommel's forces advanced rapidly eastward, laying siege to the vital seaport of Tobruk. Two Allied attempts to relieve Tobruk were defeated, but a larger offensive at the end of the year (Operation Crusader) repelled Rommel's forces after heavy fighting.

The war between the Allied and Italian navies swung decisively in favor of the Allies on March 28, 1941, when Admiral Cunningham's ships encountered the main Italian fleet south of Cape Matapan, at the southern extremity of the Greek mainland. At the cost of a couple of aircraft shot down, the Allies sank five Italian cruisers and three destroyers, and damaged the modern battleship Vittorio Veneto. The Italian Navy was emasculated as a fighting force, and the Allied task of moving troops across the Mediterranean to Greece was eased.

On April 6, 1941, German, Italian, Hungarian, and Bulgarian forces invaded Yugoslavia, ending with the surrender of the Yugoslav army on April 17, and the creation of client states in Croatia and Serbia. Also on April 6, Germany invaded Greece from Bulgaria. The Greek army defending the Metaxas Line was outnumbered and outmaneuvered by the rapid German advance through Yugoslavia and collapsed. Athens fell on April 27, yet the United Kingdom managed to evacuate over 50,000 troops.

Resistance broke out in Yugoslavia in mid-1941, centered around two movements: the Communist-led Partisans, commanded by Tito, and the royalist Chetniks led by Draža Mihailović. The two paramilitaries briefly cooperated in 1941 but soon fell out, with the Chetniks assuming a more ambivalent role, frequently siding with the occupying forces against the communists.

In April-May 1941, there was a short war in Iraq that resulted in a renewal of British occupation. In June, Allied forces invaded S