World War 2, a global conflict that reshaped the 20th century, officially began in September 1939. While the immediate trigger was the German invasion of Poland, the causes were deeply rooted in the political landscape of the preceding decades. Understanding why World War 2 started requires examining the ambitions of Adolf Hitler, the complex web of international alliances, and the failures of diplomacy in the face of rising aggression.
By early 1939, Adolf Hitler, the dictator of Germany, had set his sights on Poland. Driven by expansionist ideologies and a desire for Lebensraum (“living space”) for the German people, Hitler was determined to annex Polish territory. This ambition directly clashed with the existing European order established after World War 1. Poland, aware of the growing threat from Nazi Germany, had secured pledges of military support from both France and Great Britain in case of German aggression. These guarantees were intended to deter Hitler, but instead, they set the stage for a wider conflict when deterrence failed.
Hitler, despite these warnings, remained resolute in his plans to invade Poland. However, he needed to address a potential obstacle: the Soviet Union. Ideologically opposed to Nazi Germany, the Soviet Union shared a border with Poland and could potentially intervene to defend it. To neutralize this threat, Germany initiated secret negotiations with the Soviets. These talks culminated in the signing of the German-Soviet Nonaggression Pact on August 23-24, 1939, in Moscow. This pact, often known as the Molotov-Ribbentrop Pact, stunned the world. Beyond its public declaration of non-aggression, a secret protocol carved up Eastern Europe, specifically partitioning Poland between Germany and the Soviet Union. This cynical agreement removed the immediate threat of Soviet intervention and gave Hitler the green light to proceed with his plans for Poland.
With the Soviet Union neutralized, Hitler believed he could invade Poland without risking a wider European war – or so he initially thought. He initially ordered the invasion to commence on August 26th. However, news of a formal treaty of mutual assistance between Great Britain and Poland, signed on August 25th, gave him pause and led to a brief postponement. Despite this clear sign of British commitment, and further diplomatic efforts from western powers to avert war, Hitler remained undeterred. He ultimately chose to gamble that Britain and France would not honor their commitments to Poland, or that if they did, Germany could defeat them.
On August 31, 1939, at 12:40 pm, Hitler issued the final order to attack Poland, commencing at 4:45 am the following day. The German invasion began as planned on September 1, 1939. This act of aggression finally forced the hands of Britain and France. Honoring their pledges to Poland, Great Britain declared war on Germany at 11:00 am on September 3rd, followed by France at 5:00 pm on the same day. These declarations transformed a regional conflict into a European war, which would soon escalate into World War 2. The invasion of Poland, therefore, served as the catalyst, but the deeper causes lay in Hitler’s expansionist ambitions, strategic miscalculations, and the breakdown of international diplomacy in the face of aggression.
