The First World War (1914-1918) was the deadliest, most destructive war that had occurred in history up to that time; it was of a scale unknown to previous generations. Nonetheless, the Second World War (1939-1945) proved to be by far deadlier than the First One. Both World War I and World War II were total wars fought between the major industrial nations and their empires and both were wars of attrition, in which any means and weapons became justified in order to make the enemy unconditionally surrender. Understanding the differences of the causes of both wars is important to determine why two conflicts of a similar nature occurred under different circumstances and therefore be able to prevent other worldwide catastrophes of that kind.
The long-term causes of the Second World War differ in some ways from those of the First World War: World War I was caused by imperial rivalry and rivalry over trade and markets while World War II was triggered by the impact the Treaty of Versailles had on the defeated nations; the alliances and treaties that existed between the Great Powers were another long-term cause of World War I, while the League of Nations was a cause World War II. The short-term causes of the Second World War also differ in some ways from those of the First World War: political and social unrest in the Balkans caused World War I, while the economic and political factors after 1929 caused World War II; mobilization led to WWI vs. appeasement that led to WWII; however, the Second World War was triggered by a unique short-term cause: ideology.
Both World War I and World War II were caused by long-term tensions between the Great Powers of Europe: the impact the Treaty of Versailles had on defeated nations was one of the main long-term causes of the Second World War, which differs from the imperial rivalry and rivalry over trade and markets that were a main long-term cause of the First World War. Imperial rivalry had existed between the Great Powers of Europe – Austria-Hungary, Britain, France, Germany, and Russia – and their empires since the late 19th century. Several conflicts had arisen due to this rivalry, which had not led to war: France and Britain were rivals in North Africa and almost went to war in 1898, France and Germany disputed during the Moroccan Crises in 1905 and 1911 and over the Alsace-Lorraine region in 1871, and Russia’s Asian empire threatened Japan and Britain. This imperial rivalry led to rivalry over trade and markets, since the Great Powers wanted to acquire territories to obtain raw materials as well as markets to sell their goods overseas.
Hence, the Great Powers scrambled to dominate Africa and several conflicts developed, such as the Boer War in 1899 between Britain and Netherlands to control South Africa. All these rising tensions between the Great Powers are similar to the tensions caused by the Treaty of Versailles, which eventually led to the deadliest war in the history of the world. Germany had not been totally defeated in 1918 and, with insufficient supplies and increasing number of USA troops, simply felt unlikely to win the war. However, there was no unconditional surrender and the armistice was only an agreement to stop fighting, yet the Treaty of Versailles treated Germany as if it had unconditionally surrendered. Germany had many internal problems and had to accept this agreement, yet no German state would ever be able to accept the consequences of the Treaty in the long-term: Germany had lost its overseas colonies and had to accept an army of 100,000 men, among other restrictions. Russia, Italy, and Japan were almost completely left out of the Treaty and did not gain what they had expected when they joined the Great War. These tensions were a major cause that led to the Second World War.
Although both wars were caused by existing tensions, the tensions in World War I were caused by colonization, imperialism, and ambition; while the tensions in World War II were caused by peace agreements. Moreover, the alliances and treaties that existed among the Great Powers in Europe were another long-term cause of World War I, while the League of Nations was a long-term cause World War II. Both the alliance system and the League of Nations formed coalitions that would later lead to war. Nonetheless, the alliances that caused World War I were defensive alliances and each country had the moral obligation to support their allies, while the League of Nations’ main objective was to prevent conflicts escalating into war. Another major difference between the existing alliances in Europe before WWI and the League of Nations is that the alliances and treaties meant that more countries would actually get in involved in the First World War. What could have been a conflict only between Serbia an Austria-Hungary turned into a total war as every nation decided to aid its allies. The League of Nations, on the other hand, led to war because it failed to control aggression of larger powers.
The USA did not join the League of Nations and the USSR was a member only between 1934 and 1939; therefore, it depended on Britain and France, which were not prepared to control Germany’s, Italy’s, and Japan’s aggressions. Hence, the alliances and treaties that existed before 1914 led to WWI for the opposite reason that the League of Nations led to WWII: the treaties meant that countries would aid their allies in war, while the League was not able to aid any country that was being attacked and its lack of aid led to war. In the First World War, nations were prepared to confront aggression of their allies, unlike WWII in which nations believed that it was the job of the League to confront aggression in the name of peace. Furthermore, the economic and political factors after 1929 were a short-term cause of the Second World War, which differs from the political and social unrest in the Balkans that led to the First World War. The Balkans was part of the Ottoman Empire but had just broken up into independent, unstable states.
Various ethnic and religious groups existed in these states and many people found themselves as the minority of a newly created nation. Austria-Hungary and Russia competed to occupy the Balkans. The social and political divisions in the Balkans led to the Bosnian Crisis of 1908. Austria occupied Bosnia-Herzegovina since 1878 and it was agreed that it would eventually absorb it and Russia would move its warships from the Black Sea to the Mediterranean. In October 1908, Austria annexed Bosnia-Herzegovina but Russia was humiliated. This annexation also led to more social and internal problems and the development of the Black Hand, which would eventually kill Archduke Franz Ferdinand of Austria in 1914 and lead to war. Unlike the social unrest that was present in the Balkans for several time and that had caused conflicts even before WWI, the economic crisis after 1929 had resulted in political conflicts and all these led to WWII. The German economic crisis was triggered by the US stock market crash in October 1929, the decreasing agricultural prices, the collapse of the German banks, and the rapid unemployment within the country.
This economic crisis led to the rise of extremist groups in Germany that offered solutions: Communists offered social revolution and Nazis stood for national revival and Lebensraum. The Bosnian Crisis caused even more social and political divisions within the Balkans and this later led to war. On the contrary, the economic and political crises in Germany led to its unification and the rise of a single-party state. Hence, WWI was caused by divisions, while WWII was caused by unification and nationalism. Not only this, but appeasement was another short-term cause of the Second World War that differs from mobilization which was a short-term cause of the First World War. Since the end of the 19th century, the Great European Powers began mobilizing, meaning that they put their nation ready for war, called up reserves and made the first moves to put military plans into operation. After Austria declared war on Serbia on July 28, 1914, Russia ordered partial mobilization on the 29th. In response to this, Germany mobilized on the 30th and France then mobilized on August 1st. In the end, these mobilizations led to the declaration of war of each country.
Thus, mobilization was the final step that led to war. Appeasement was the opposite of this, as countries saw Germany’s plans and actions and did nothing. Appeasement showed the weakness of these nations and made war likelier. Hitler left the League of Nations in 1933, reintroduced conscription and invaded Ethiopia in 1935, remilitarized the Rhineland in 1936, annexed Austria in 1938, invaded Poland on September 1, 1939, among other actions, and the League of Nations and Great Powers did not do anything about it to prevent another catastrophe. Unlike WWI in which the European Powers tried to end conflicts by mobilizing and threatening the enemies, the British and French tried to find a peaceful solution that would not involve going to war in the 1930s. Finally, the Second World War was deeply influenced by a unique short-term cause: ideology. Germany invaded Poland on September 1, 1939 not only to regain its lost territory, but also to expand its living space at the expense of supposedly racially inferior people, who were enslaved or killed by the Nazis. World War II was increasingly driven by the ideological struggle between Nazism and Communism.
According to the Nazis, Jews and Communists were linked and were making a conspiracy to control the world. The Nazis wanted to prove the superiority of their system. In addition, they wanted to create a racially pure state by exterminating millions of Jews, gypsies, homosexuals, and other asocials. All these led to war. Nevertheless, neither political nor racial ideology was one of the causes of the First World War. The long-term causes of the Second World War differ in some ways from those of the First World War. Both wars were caused by long-term tensions between the Great Powers, yet the tensions that led to WWI were a result of the ambitions and rivalry of imperialism, while the tensions that led to WWII were the result of the previous war and its peace agreements. The relationship between the Great Powers was another long-term cause of both wars: the treaties that existed between them and the need to defend and aid each others’ allies led to many countries intervening in WWI; however, the League of Nations failed to intervene and stop the aggressions, which led to WWII.
The short-term causes of the Second World War also differ in some ways from those of the First World War: the political and social unrest in the Balkans resulted in many divisions that led to WWI. Unlike this, the economic and political factors after 1929 in Germany resulted in the unification of its people and the rise of nationalism which was a major cause of WWII. Mobilization was another short-term cause of WWI, against appeasement, which allowed Germany to continue with its aggressions, and eventually led to WWII. Ideology, a short-term cause of WWII, differed from all the causes of WWI. Understanding and analyzing the reasons and causes of wars – especially of the most destructive ones – and the relationship and differences between them try to prevent other catastrophes from happening. It is a way to learn from humanity’s past mistakes and try to progress and build a better future. Hopefully one day the following famous phrase will be finally achieved: “Never again… and this time we mean it.”