HIST103: World History (1600–Present)

Commonly held general causes for World War II are the rise of nationalism, militarism, and unresolved territorial issues. In Germany, resentment of the harsh Treaty of Versailles – specifically article 231 (the "Guilt Clause"), the belief in the Dolchstosslegende (that treachery had cost them World War I), and the onset of the Great Depression – fueled the rise to power of Adolf Hitler's militarist National Socialist German Workers Party (the Nazi Party). Meanwhile, the treaty's provisions were laxly enforced due to fear of another war. Closely related is the failure of the British and French policy of appeasement, which sought to avoid war but actually gave Hitler time to re-arm. The League of Nations proved to be ineffective.

Japan, ruled by a militarist clique devoted to becoming a world power, invaded China to bolster its meager stock of natural resources. This angered the United States, which reacted by making loans to China, providing covert military assistance, and instituting increasingly broad embargoes of raw materials against Japan. These embargoes would have eventually wrecked Japan's economy; Japan was faced with the choice of withdrawing from China or going to war in order to conquer the oil resources of the Dutch East Indies (Indonesia). It chose to proceed with plans for the Greater East Asia War in the Pacific.

War Breaks Out in Europe: 1939

Pre-War Alliances

In March 1939, when German armies entered Prague and then occupied the remainder of Czechoslovakia, the Munich Agreement – which required Germany to peacefully resolve its claim to the Czech territory – collapsed. On May 19, Poland and France pledged to provide each other with military assistance in the event either was attacked. The British had already offered support to the Poles in March; then, on August 23, Germany and the Soviet Union signed the Molotov-Ribbentrop Pact.

The pact included a secret protocol that would divide Eastern Europe into German and Soviet areas of interest. Each country agreed to allow the other a free hand in its area of influence, including military occupation. Hitler was now ready to go to war in order to conquer Poland. The signing of a new alliance between Britain and Poland on August 25 deterred him for only a few days.

Invasion of Poland

On September 1, Germany invaded Poland. Two days later, Britain and France declared war on Germany. The French mobilized slowly, then mounted 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. Meanwhile, on September 9, the Germans reached Warsaw, having slashed through the Polish defenses.

On September 17, Soviet troops occupied eastern Poland, taking control of territory that Germany had agreed was in the Soviet sphere of influence. A day later, the Polish president and commander-in-chief both fled to Romania. The last Polish units surrendered on October 6. Some Polish troops evacuated to neighboring countries. In the aftermath of the September Campaign, occupied Poland managed to create a powerful resistance movement, and Poles made a significant contribution to the Allies' cause 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.

Battle of the Atlantic

Meanwhile, in the North Atlantic, German U-boats operated against Allied shipping. The submarines were made up of skill, luck, and daring, which they lacked in numbers. One U-boat sank the British aircraft carrier HMS Courageous, while another managed to sink the battleship HMS Royal Oak in its home anchorage of Scapa Flow. Altogether, U-boats sank more than 110 vessels in the first four months of the war.

In the South Atlantic, the German pocket battleship Admiral Graf Spee raided Allied shipping, then was scuttled after the battle of the River Plate. About a year and a half later, another German raider, the battleship Bismarck, suffered a similar fate in the North Atlantic. Unlike the U-boat threat, which had a serious impact later in the war, German surface raiders had little impact because their numbers were so small.

War Spreads: 1940

Soviet-Finnish War

The Soviet Union attacked Finland on November 30, 1939, starting the Winter War. Finland surrendered to the Soviet Union in March 1940 and signed the Moscow Peace Treaty (1940), in which the Finns made territorial concessions. Later that year, in June, the Soviet Union occupied Latvia, Lithuania, and Estonia and annexed Bessarabia and Northern Bukovina from Romania.

Invasion of Denmark and Norway

The evolution of German plans for the invasion of France.

Germany invaded Denmark and Norway on April 9, 1940, in part to counter the threat of an impending Allied invasion of Norway. Denmark did not resist, but Norway fought back, assisted by British, French, and Polish (exile) forces landing in support of the Norwegians at Namsos, Åndalsnes, and Narvik. By late June, the Allies were defeated, German forces were in control of most of Norway, and what remained of the Norwegian Army had surrendered.

Invasion of France and the Low Countries

Heinkel He 111 over London on 7 September 1940

On May 10, 1940, the Germans invaded Luxembourg, Belgium, the Netherlands, and France, ending the "Phony War." The British Expeditionary Force (BEF) and the French Army advanced into northern Belgium, planning to fight a mobile war in the north while maintaining a static continuous front along the Maginot Line, built after World War I, further south.

In the first phase of the invasion, Fall Gelb (CACA), the Wehrmacht's Panzergruppe von Kleist raced through the Ardennes, broke the French line at Sedan, then slashed across northern France to the English Channel, splitting the Allies in two. Meanwhile, Belgium, Luxembourg, and the Netherlands fell quickly against the attack of German Army Group B. 

The British Expeditionary Force, encircled in the north, was evacuated from Dunkirk in Operation Dynamo. 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), advancing behind the Maginot Line and near the coast. France signed an armistice with Germany on June 22, 1940, leading to the establishment of the Vichy France puppet government in the unoccupied part of France.

Battle of Britain

Following the defeat of France, Britain chose to fight on, so Germany began preparations in the summer of 1940 to invade Britain (Operation Sea Lion), while Britain made anti-invasion preparations. Germany's initial goal was to gain air control over Britain by defeating the Royal Air Force (RAF). The war between the two air forces became known as the Battle of Britain.

The Luftwaffe initially targeted RAF Fighter Command. The results were not as expected, so the Luftwaffe later turned to terror bombing London. The Germans failed to defeat the Royal Air Force. Thus, Operation Sea Lion was postponed and eventually canceled.

North African Campaign

Italy declared war in June 1940, which challenged British supremacy of the Mediterranean, hinged on Gibraltar, Malta, and Alexandria. Italian troops invaded and captured British Somaliland in August. In September, the North African Campaign began when Italian forces in Libya attacked British forces in Egypt.

The aim was to make Egypt an Italian possession, especially the vital Suez Canal east of Egypt. British, Indian, and Australian forces counter-attacked in Operation Compass. This offensive stopped in 1941 when much of the Commonwealth forces were transferred to Greece to defend it from German attack. However, German forces (known later as the Afrika Korps) under General Erwin Rommel landed in Libya and renewed the assault on Egypt.

Invasion of Greece

Italy invaded Greece on October 28, 1940, from bases in Albania after the Greek Premier John Metaxas rejected an ultimatum to hand over Greek territory. Despite the enormous superiority of the Italian forces, the Greek army forced the Italians into a massive retreat deep into Albania. By mid-December, the Greeks occupied one-fourth of Albania. The Greek army had inflicted upon the Axis Powers their first defeat in the war, and Nazi Germany would soon be forced to intervene.

War Becomes Global: 1941

European Theater

Lend-Lease

The extent of the Axis conquests during World War II

U.S. President Franklin Delano Roosevelt signed the Lend-Lease Act on March 11. This program was the first large step away from American isolationism, providing substantial assistance to the United Kingdom, the Soviet Union, and other countries.

Invasion of Greece and Yugoslavia

Yugoslavia's government succumbed to the pressure of the Axis and signed the Tripartite Treaty on March 25. The government was overthrown in a coup, which replaced it with a pro-Allied government. This prompted the Germans to invade Yugoslavia on April 6. In the early morning, Germans bombarded Belgrade with an estimated 450 aircraft. Yugoslavia was occupied in a matter of days, and the army surrendered on April 17, but the partisan resistance lasted throughout the war.

However, the rapid downfall of Yugoslavia allowed German forces to enter Greek territory through the Yugoslav frontier. The 58,000 British and Commonwealth troops who had been sent to help the Greeks were driven back and soon forced to evacuate. On April 27, German forces entered Athens, which was followed by the end of organized Greek resistance. The occupation of Greece proved costly, as guerilla warfare continually plagued the Axis occupiers.

Invasion of the Soviet Union

Operation Barbarossa, the largest invasion in history, began on June 22, 1941. An Axis force of over four million soldiers advanced rapidly deep into the Soviet Union, destroying almost the entire Western Soviet army in huge battles of encirclement. The Soviets dismantled as much industry as possible ahead of the advancing forces, moving it to the Ural Mountains for reassembly.

By late November, the Axis had reached a line at the gates of Leningrad, Moscow, and Rostov, at the cost of about 23 percent casualties. Their advance then ground to a halt. The German General Staff had underestimated the size of the Soviet army and its ability to draft new troops. They were now dismayed by the presence of new forces, including fresh Siberian troops under General Zhukov, and by the onset of a particularly cold winter.

German forward units had advanced within distant sight of the golden onion domes of Moscow's Saint Basil's Cathedral. Then, on December 5, the Soviets counter-attacked and pushed the Axis back some 150-250 kilometers (100-150 mi), which became the first major German defeat of World War II.

The Continuation War between Finland and the Soviet Union began on June 25, with Soviet air attacks shortly after the beginning of Operation Barbarossa.

Allied Conferences

The Atlantic Charter was a joint declaration by Churchill and Roosevelt on August 14, 1941.

In late December 1941, Churchill met Roosevelt again at the Arcadia Conference. They agreed that defeating Germany had priority over defeating Japan. The Americans proposed a 1942 cross-channel invasion of France, which the British strongly opposed, suggesting instead a small invasion in Norway or landings in French North Africa.

Mediterranean

German paratroopers landing on the island of Crete.

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 drove Rommel back after heavy fighting.

On May 20, the Battle of Crete began when elite German parachute and glider-borne mountain troops launched a massive airborne invasion of the Greek island. Crete was defended by Greek and Commonwealth troops. The Germans attacked the island's three airfields simultaneously. Their invasion of two airfields failed, but they successfully captured one, which allowed them to reinforce their position and capture the island in a little over one week.

In June 1941, Allied forces invaded Syria and Lebanon, capturing Damascus on June 17. In August, British and Soviet troops occupied neutral Iran to secure its oil and a southern supply line to Russia.

Pacific Theater

Sino-Japanese War

Overview map of World War II in Asia and the Pacific: Allies green, Japanese conquests yellow.

A war had begun in East Asia before World War II began in Europe. On July 7, 1937, Japan, after occupying Manchuria in 1931, launched another attack against China near Beijing. The Japanese made initial advances but were stalled at Shanghai. The city eventually fell to the Japanese, and in December 1937, the capital city of Nanking (now Nanjing) fell. As a result, the Chinese government moved its seat to Chongqing for the rest of the war.

The Japanese forces committed brutal atrocities against civilians and prisoners of war when Nanking was occupied, slaughtering as many as 300,000 civilians within a month. By 1940, the war had reached a stalemate, with both sides making minimal gains. The Chinese had successfully defended their land from oncoming Japanese on several occasions, while strong resistance in areas occupied by the Japanese made a victory seem impossible to the Japanese.

Japan and the United States

Pearl Harbor under attack on December 7, 1941

In the summer of 1941, the United States began an oil embargo against Japan, which was a protest to Japan's incursion into French Indo-China and the continued invasion of China. Japan planned an attack on Pearl Harbor to cripple the U.S. Pacific Fleet before consolidating oil fields in the Dutch East Indies.

On December 7, a Japanese carrier fleet launched a surprise air attack on Pearl Harbor, Hawaii. The raid resulted in two U.S. battleships sunk and six damaged but later repaired and returned to service. The raid failed to find any aircraft carriers and did not damage Pearl Harbor's usefulness as a naval base. The attack strongly united public opinion in the United States against Japan.

The following day, December 8, the United States declared war on Japan. On the same day, China officially declared war against Japan. Germany declared war on the United States on December 11, even though it was not obliged to do so under the Tripartite Pact. Hitler hoped that Japan would support Germany by attacking the Soviet Union. Japan did not oblige, and this diplomatic move by Hitler proved a catastrophic blunder that unified American public support for the war.

Japanese Offensive

Lt Gen Arthur Percival surrendered Singapore to the Japanese on February 15, 1942. It was the greatest defeat in British history.

Japan soon invaded the Philippines and the British colonies of Hong Kong, Peninsular Malaysia, Borneo, and Burma, with the intention of seizing the oilfields of the Dutch East Indies. Despite fierce resistance by American, Philippine, British, Canadian, and Indian forces, all these territories capitulated to the Japanese in a matter of months. The British island fortress of Singapore was captured in what Churchill considered one of the most humiliating British defeats of all time.