The outbreak of World War II was caused by a long chain of events and in many respects it was inevitable. The most obvious causes can be divided into several categories, including territorial disputes, colonial disputes and rivalry between the major powers. Not so obvious, but equally important causes include the emergence of the USSR and a mere fact that the war was desired by all major powers. In fact, two World Wars can be united into a one prolonged military conflict, for—despite of some peaceful years in Europe—the warfare continued in the interwar period (e.g. Japanese aggression in China, Italian aggression in Ethiopia, Soviet aggression in Finland). However, there were certain developments, which greatly triggered the forthcoming global war. These developments are discussed in this paper.
The first and probably most important event was the end of the World War I and the Treaty of Versailles. After the collapse of the Austro-Hungarian and Russian Empires nine new states appeared at the map. Their borders were not clearly defined, and in many cases there were disputes about literally every inch of land. Romania argued with Hungary about Transylvania and with Bulgaria about Dobrudja, Bulgaria demanded Thrace from Greece and Macedonia from Yugoslavia, Germany had a conflict with Poland and Czechoslovakia because of Silesia and the Sudetenland. In addition, the countries which had lost some parts of their territory sought to return them. The long history of Europe does not know any better way to solve such issues, including territorial disputes, except by means of war, and the beginning of World War II was inevitable. It was impossible to think that Germany, which was erased from the world history after its defeat would not dream about a rematch. Deprived of the opportunity to have its own army (other than voluntary, the number of which could not exceed 100 thousand soldiers with light weapons) and suppressed by terrible reparations, Germany, which was used to the role of one of the world’s empires, could not accept the loss of its dominance. Beginning of the Second World War in this aspect was only a matter of time.
A significant increase in the number of dictatorships created additional prerequisites to the outbreak of violent conflict. Paying great attention to the development of the army and weapons, first as a means to suppress possible internal unrest, and then as a way to gain new lands, Asian and European dictators in every way advanced the beginning of the Second World War. However, this concerns the democracies as well. For the U.S., for example, war was a means of ending the Great Depression.
The role of the new socialist state (the USSR) that emerged from the ruins of the Russian Empire as a stimulus for the U.S. and Europe is difficult to overestimate. The rapid development of the communist movement in a number of capitalist countries motivated by the existence of such a clear example of victorious socialism could not instill fear and the attempt to destroy the Soviet Union would have been made inevitably.
The policy of appeasement became one of the major causes of the forthcoming war. Adopting the policy of appeasement before World War II the Western nations (especially Britain and France) had hoped that by making concessions and compromises they would be able stop the aggressor. Thus, Britain and France, closing the eyes to the Nazi aggression (blaming Germany only in words), had hoped that the ambitions of Germany would be met satisfied at the expense of the weaker states (Austria and Czechoslovakia, for example). Britain and France signed non-aggression treaties with Germany, openly directing the Nazi aggression eastward against the USSR. The Soviet Union as a result became politically isolated, which later led to another major event – the Molotov-Ribbentrop agreement. At the summit in Munich, the prime ministers of Britain and France, Neville Chamberlain and Edouard Daladier agreed to the inclusion of the Sudetenland to Germany (Munich Agreement), despite the fact that this territory had never belonged to Germany. In March 1939, Germany occupied Czechoslovakia and turned the Czech Republic into the Protectorate of Bohemia and Moravia, and Slovakia as its satellite, but formally an independent state. Under the threat of military force Poland receives Teschen Silesia, and Hungary part of Slovakia (which clearly demonstrates “peaceful” intentions of the countries, which later claimed the status of victims).
As it was stated above, the direct result of the policy of appeasement was the signing in August 1939 of the Treaty of Non-Aggression between Germany and the Soviet Union and the secret protocol to it. Soviet leaders become aware of the impending German invasion of Poland. Stalin and Hitler decided the partition of Poland between Germany and the USSR at Curzon Line, the border between Russia and Poland, which was suggested during the establishment of new borders after World War I. In the event of a German-Polish war, the Soviet Union was to enter the territory of western Ukraine and western Belarus, which were given to Poland after the Soviet-Polish war of 1920. The Soviet sphere of interest also included the parts of Russia before 1917 – Latvia and Estonia. Now Hitler could attack Poland and not be afraid of Stalin’s reaction. He probably did not really believe in the possibility of French and British intervention. His assumption was partly proved by the early period of the war, better known as the Phoney War.
As a matter of fact, the war could have probably been finished by 1939 if Britain and France had not waited so long. The name “Phoney War” emphasized the nature of hostilities between the warring parties – the almost complete lack of them, with the exception of naval warfare. Warring sides only had some local fighting at the Franco-German border, mostly under the protection of the Maginot and Siegfried defensive lines. The Phony War was used by Germany’s military command as a strategic pause. This allowed Germany to successfully implement the Polish campaign, Operation Weserübung (assault on Denmark and Norway) and to prepare the Manstein Plan (assault on France through Belgium).
The above mentioned events, along with many others, became the most important developments, which led to the greatest conflict in history.