World War II

In late August 1939, Hitler and Soviet leader Joseph Stalin signed the German-Soviet Nonaggression Pact, which incited a frenzy of worry in London and Paris. Hitler had long planned an invasion of Poland, a nation to which Great Britain and France had guaranteed military support if it was attacked by Germany. The pact with Stalin meant that Hitler would not face a war on two fronts once he invaded Poland, and would have Soviet assistance in conquering and dividing the nation itself. On September 1, 1939, Hitler invaded Poland from the west; two days later, France and Britain declared war on Germany, beginning World War II.

On September 17, Soviet troops invaded Poland from the east. Under attack from both sides, Poland fell quickly, and by early 1940 Germany and the Soviet Union had divided control over the nation, according to a secret protocol appended to the Nonaggression Pact. Stalin’s forces then moved to occupy the Baltic States (Estonia, Latvia and Lithuania) and defeated a resistant Finland in the Russo-Finish War. During the six months following the invasion of Poland, the lack of action on the part of Germany and the Allies in the west led to talk in the news media of a “phony war.” At sea, however, the British and German navies faced off in heated battle, and lethal German U-boat submarines struck at merchant shipping bound for Britain, sinking more than 100 vessels in the first four months of World War II.

World War II in the West (1940-41)

On April 9, 1940, Germany simultaneously invaded Norway and occupied Denmark, and the war began in earnest. On May 10, German forces swept through Belgium and the Netherlands in what became known as “blitzkrieg, ” or lightning war. Three days later, Hitler’s troops crossed the Meuse River and struck French forces at Sedan, located at the northern end of the Maginot Line, an elaborate chain of fortifications constructed after World War I and considered an impenetrable defensive barrier. In fact, the Germans broke through the line with their tanks and planes and continued to the rear, rendering it useless. The British Expeditionary Force (BEF) was evacuated by sea from Dunkirk in late May, while in the south French forces mounted a doomed resistance. With France on the verge of collapse, Benito Mussolini of Italy put his Pact of Steel with Hitler into action, and Italy declared war against France and Britain on June 10.

On June 14, German forces entered Paris; a new government formed by Marshal Philippe Petain (France’s hero of World War I) requested an armistice two nights later. France was subsequently divided into two zones, one under German military occupation and the other under Petain’s government, installed at Vichy. Hitler now turned his attention to Britain, which had the defensive advantage of being separated from the Continent by the English Channel. To pave the way for an amphibious invasion (dubbed Operation Sea Lion), German planes bombed Britain extensively throughout the summer of 1940, including night raids on London and other industrial centers that caused heavy civilian casualties and damage. The Royal Air Force (RAF) eventually defeated the Luftwaffe (German Air Force) in the Battle of Britain, and Hitler postponed his plans to invade. With Britain’s defensive resources pushed to the limit, Prime Minister Winston Churchill began receiving crucial aid from the U.S. under the Lend-Lease Act, passed by Congress in early 1941.

Operation Barbarossa (1941-42)

By early 1941, Hungary, Romania and Bulgaria had joined the Axis, and German troops overran Yugoslavia and Greece that April. Hitler’s conquest of the Balkans was a precursor for his real objective: an invasion of the Soviet Union, whose vast territory would give the German master race the “Lebensraum” it needed. The other half of Hitler’s strategy was the extermination of the Jews from throughout German-occupied Europe. Plans for the “Final Solution” were introduced around the time of the Soviet offensive, and over the next three years more than 4 million Jews would perish in the death camps established in occupied Poland.

On June 22, 1941, Hitler ordered the invasion of the Soviet Union, codenamed Operation Barbarossa. Though Soviet tanks and aircraft greatly outnumbered the Germans’, their air technology was largely obsolete, and the impact of the surprise invasion helped Germans get within 200 miles of Moscow by mid-July. Arguments between Hitler and his commanders delayed the next German advance until October, when it was stalled by a Soviet counteroffensive and the onset of harsh winter weather.