World War II officially began on September 1, 1939, with Germany’s invasion of Poland. Before this, Germany and the Soviet Union had signed a non-aggression pact, which secretly included provisions for the partition of Poland between the two nations. Efforts to forge an understanding between the Soviet Union, Britain, and France had failed, primarily because Britain and France underestimated the Soviet Union’s strategic importance and did not secure a military alliance. This misstep paved the way for the Soviet-German non-aggression pact and Germany’s subsequent attack on Poland.
Despite prior assurances from Britain and France to support Poland in the event of aggression, their efforts to deter war proved unsuccessful. When Germany invaded Poland, Britain and France declared war on Germany on September 3, 1939. Soon after, other countries also entered the conflict, aligning with either the Allies or the Axis powers.
In Asia, Japan had already launched aggressive campaigns against China but refrained from declaring war on the Soviet Union or the United States for a time. Italy initially remained neutral but joined the war on Germany’s side in June 1940. Germany’s victories in Europe emboldened it to launch an invasion of the Soviet Union on June 22, 1941, bringing the USSR into the Allied camp. Meanwhile, Japan’s attack on Pearl Harbor on December 7, 1941, prompted the United States to enter the war.
The war saw the Allies—comprising Britain, France, the Soviet Union, the United States, and others—pitted against the Axis Powers of Germany, Italy, and Japan. The conflict culminated in the unconditional surrender of Italy, Germany, and Japan, in that order.
This unit will explore the conditions and factors that led to the outbreak of World War II and examine the war’s consequences. While military campaigns and battles are not the primary focus, the aftermath of the war—including peace treaties and the emergence of the United States and the Soviet Union as superpowers—will be discussed. Additionally, we will analyze how traditional great powers lost their influence in the post-war world order and the efforts made to establish peace through treaties with the defeated nations.
Table of Contents
Causes of the World War-II
Treaty of Versailles
In 1919, following the First World War, the Paris Peace Conference sought to establish an ideal world order based on peace, justice, and disarmament. However, the Treaty of Versailles ultimately became a dictated settlement, imposed on Germany by the victorious Allied powers. The treaty reflected the Allies’ lack of sincerity and was driven by divergent national interests. France, in particular, aimed to avenge its humiliation by Germany in the Franco-Prussian War of 1871.
The peace negotiations began in January 1919, but Germany, as the defeated nation, was excluded from meaningful participation. The draft treaty, prepared solely by the Allies, was handed to Germany on May 7, 1919, with a demand for written suggestions within three weeks. When the treaty’s harsh terms were made public, it provoked widespread resentment in Germany. Germans rejected the claim that they alone bore responsibility for the war and submitted numerous criticisms and proposed revisions. However, except for one minor amendment, their objections were dismissed. Ultimately, Germany was forced to sign the Treaty of Versailles on June 28, 1919. The Germans referred to it as a “diktat,” a dictated peace they found deeply humiliating.
The treaty imposed severe penalties on Germany. It stripped Germany of all its overseas colonies and significantly reduced its territory in Europe, with Poland, France, and Belgium gaining at its expense. Germany’s military capabilities were drastically curtailed—its army and navy were reduced, and it was prohibited from maintaining an air force. Furthermore, Germany was declared guilty of war crimes and obligated to pay massive reparations to the victors.
The Treaty of Versailles devastated and humiliated Germany, sowing the seeds of resentment and revenge. The economic and political instability it caused contributed to the rise of Adolf Hitler and the Nazi Party, whose nationalist rhetoric promised to restore German pride and avenge the nation’s disgrace. This drive for retribution ultimately set the stage for World War II, just two decades later.
Failure of the Collective Security System
The concept of a collective security system emerged as a promising ideal at the end of the First World War. World leaders envisioned a framework where all nations would collectively ensure the security of any victim of international aggression. The Covenant of the League of Nations outlined that, in the event of aggression, League members would act together to compel the aggressor to retreat. This collective action could involve economic sanctions, military support for the victim, or both.
However, during the interwar years, the League of Nations proved ineffective when faced with aggression by major powers. In 1931, Japan invaded China and, by mid-1932, had seized Manchuria, establishing the puppet state of Manchukuo. Japan justified its actions to the League as self-defense, claiming it was merely a police action. Despite the League’s call for member states not to recognize Manchukuo, Japan left the League but maintained control over the territory.
Similarly, in 1935, Italy invaded Abyssinia (Ethiopia), defeated it, and annexed it into the Italian Empire in 1936. Although the League declared Italy an aggressor and imposed economic sanctions, it failed to take decisive military action against a major power and permanent League Council member. The League also remained powerless against Germany’s aggressive actions, such as violating the military clauses of the Treaty of Versailles (1935), remilitarizing the Rhineland (1936), annexing Austria (1938), and dismantling Czechoslovakia (1938–1939).
The failure of the collective security system undermined the League of Nations’ credibility and proved to be a significant factor in the outbreak of World War II.
Failure of Disarmament
The Paris Peace Conference of 1919 emphasized that world peace could be secured only if nations reduced their armaments to levels necessary for self-defense. Offensive weapons were to be eliminated, and the League of Nations was tasked with formulating a disarmament strategy. In 1920, the League created a Temporary Mixed Commission to address disarmament, but progress stalled as France insisted on ensuring its security before agreeing to demilitarization.
In 1925, a Preliminary Commission was established to identify offensive weapons, but conflicting national perspectives hindered progress. Finally, in February 1932, a Disarmament Conference convened in Geneva. However, mutual distrust and conflicting interests among nations led to its failure after prolonged discussions.
Germany, disarmed by the Treaty of Versailles, expected the victorious nations to follow suit, but they did not. Frustrated, Germany withdrew from the Disarmament Conference and the League of Nations in October 1933. By 1935, Germany openly renounced the military restrictions of the Treaty of Versailles and began rearming on a large scale. Other nations were already stockpiling arms, and Germany’s rearmament triggered an arms race that ultimately culminated in armed conflict.
The failure of disarmament became another critical factor leading to the outbreak of the Second World War.
World Economic Crisis
The global financial crisis began in 1929 when American financial institutions abruptly ceased advancing loans to European nations. Many countries, particularly Germany, had been achieving rapid industrial growth primarily with borrowed American funds. The crisis reached its peak during 1930–1932, severely impacting economies worldwide. Germany was hit the hardest, with nearly 700,000 people losing their jobs. The financial strain forced Germany to announce it could no longer pay reparations.
Out of Germany’s economic turmoil emerged the Nazi regime under Adolf Hitler. Appointed Chancellor in 1933, Hitler quickly dismantled democracy and established a dictatorship. Meanwhile, other nations, including England, faced economic hardships, such as abandoning the gold standard. Germany, Japan, and Italy exploited the global financial crisis to pursue aggressive policies, forming the Fascist Axis that significantly contributed to the outbreak of World War II.
Rome-Berlin-Tokyo Axis
On the eve of World War II, Europe witnessed the emergence of another antagonistic bloc. Germany, Japan, and Italy came together to form the Rome-Berlin-Tokyo Axis, building on shared fascist ideologies and imperialist ambitions. This alliance was formalized between 1936 and 1937 through the Anti-Comintern Pact. The Axis Powers openly opposed peaceful conflict resolution, glorified war, and exploited weaker nations like China, Austria, Czechoslovakia, Albania, and Poland.
Their aggressive actions, including territorial expansions and militaristic policies, alarmed Britain and France. Although these nations sought closer cooperation, their attempts to form an Anglo-French-Soviet alliance failed. Distrust and a desire to appease Hitler led Britain and France to ignore Soviet Union’s proposals for a military pact. This diplomatic failure culminated in the Soviet-German Non-Aggression Pact, which shocked the world and paved the way for Germany’s invasion of Poland, triggering World War II.
The Problem of National Minorities
The peace settlements following World War I led to the creation of new nation-states in Europe, often leaving behind large ethnic minorities. While President Wilson of the United States had advocated for self-determination, the principle was only partially implemented due to strategic considerations. Consequently, significant German minorities were left in Poland and Czechoslovakia, alongside Russian minorities in Poland and Romania. Despite the Minority Treaties established after the Paris Peace Conference, approximately 750,000 Germans remained under foreign rule.
Hitler capitalized on these grievances, using the alleged mistreatment of German minorities in Czechoslovakia and Poland as a pretext for aggression. This justification led to the annexation of Austria, the dismemberment of Czechoslovakia, and, ultimately, the invasion of Poland. Thus, the issue of minorities became a key factor and an excuse for the outbreak of World War II.
Appeasement by Britain and France
The policy of appeasement pursued by Britain and France toward Nazi-Fascist dictators was a significant cause of World War II. After World War I, British and French foreign policies diverged. Britain, concerned about France’s growing influence, sought to maintain the balance of power in Europe and even supported Germany against France during the interwar years.
When Hitler rose to power and Germany allied with Italy, Britain drew closer to France, which needed British support against an increasingly hostile Germany. British foreign policy, motivated by fears of communism, sought to challenge the Soviet Union and undermine leftist governments in France and Spain. This led Britain, and subsequently France, to adopt a policy of appeasement toward Hitler and Mussolini.
The appeasement policy became evident through actions such as Britain’s support for Mussolini during the Abyssinian War, the Munich Agreement’s concessions to Hitler, and the failure to protect weaker nations like Austria and Albania. Initiated under Baldwin and pursued aggressively by Neville Chamberlain, the appeasement policy emboldened the Axis Powers, paving the way for World War II.
Events of World War-II
German Attack on Poland
The immediate and decisive cause of World War II was Germany’s invasion of Poland on September 1, 1939. This invasion followed the failure of Anglo-French efforts to form an alliance with the Soviet Union. Instead, Hitler shocked the world by signing a non-aggression pact with Stalin, despite years of mutual animosity between Nazi Germany and Soviet Russia.
The agreement, known as the Molotov-Ribbentrop Pact, included a secret protocol that divided Eastern Europe into German and Soviet spheres of influence. This secret plan, which only became public in 1945, effectively sanctioned the partition of Poland. Germany launched its invasion from the west, and on September 17-18, 1939, Soviet forces attacked from the east. By September 28, Poland was formally divided under the Soviet-German Frontier and Friendship Treaty.
Britain and France, having guaranteed Poland’s security, declared war on Germany on September 3, 1939. However, while other nations also declared war on Germany, many of these declarations were symbolic. Even Britain and France were still mobilizing their forces, leaving Poland to be overrun.
The War Begins
The German invasion of Poland set World War II into motion, but tensions had been escalating prior to this event. On March 23, 1939, German troops quietly occupied Memel, a German-majority city under Lithuanian control, after Hitler demanded its surrender. On the same day, German Foreign Minister Joachim von Ribbentrop presented Poland with a set of demands. These included the return of the city of Danzig (already under Nazi influence) to Germany, and the establishment of a highway and rail corridor through the Polish Corridor to connect East Prussia with the rest of Germany.
Hitler anticipated that Britain might repeat its policy of appeasement, as seen during the Munich Agreement, but this time Britain took a firm stance. Prime Minister Neville Chamberlain unambiguously guaranteed Poland’s security. Similar assurances were later extended to Greece and Romania when Italy annexed Albania on April 7, 1939. France and Britain also began conscription, signaling their readiness for conflict.
In response, Hitler abandoned the 1934 Polish-German Non-Aggression Pact and the 1935 Anglo-German Naval Agreement. Meanwhile, Germany solidified its alliance with Japan and Italy through the Anti-Comintern Pact (1936–1937), which ostensibly targeted global communism but was, in reality, a coalition against the Soviet Union.
By August 1939, Hitler was ready to resolve the Polish issue on his terms and sought a pretext for war. On August 29, he instructed the British Ambassador in Berlin to arrange for a fully empowered Polish delegation to arrive in Berlin the following day for negotiations. This unusual and unreasonable demand was clearly designed to fail, as it left no time for diplomatic preparation.
When no Polish delegation arrived on August 30, Hitler used this as justification for his long-planned invasion. On September 1, 1939, German forces launched a full-scale attack on Poland. Britain and France, staying true to their commitments, declared war on Germany on September 3. On September 18, the Soviet Union invaded Poland from the east.
Despite these developments, Italy and the United States remained out of the conflict at this stage. Efforts for diplomatic resolution continued briefly, but Germany was resolute in its pursuit of total war, marking the full outbreak of World War II.
USA and USSR Become Allies
At the outset of World War II, Germany and Italy were close political allies. However, the Soviet-German Non-Aggression Pact of 1939 disappointed Mussolini, and Italy initially refrained from entering the war until June 1940. When France was nearing defeat, Italy joined Germany against France and the Allies. Meanwhile, the Soviet Union stayed out of the main conflict but collaborated with Germany by invading Poland. The USSR also attacked Finland, leading to its expulsion from the League of Nations.
Stalin continued to trust Hitler, even as the Nazi leader defeated most of Europe’s neighbors. However, this trust was shattered on June 22, 1941, when Germany launched Operation Barbarossa, a massive invasion of the Soviet Union. Before this betrayal, Stalin had coerced the Baltic nations—Latvia, Lithuania, and Estonia—into joining the USSR as Union Republics, threatening them with German aggression if they refused. Similarly, Stalin recovered Bessarabia and Bukovina from Romania, securing territorial gains without officially entering the war.
Hitler, meanwhile, achieved significant victories, including France’s surrender in June 1940. However, he failed to bring Spain into the Axis fold, as General Franco kept Spain neutral throughout the war.
In the United States, public opinion strongly opposed entering the war. The Neutrality Act of 1937 prohibited the sale of armaments to warring nations. However, as Germany began attacking western democracies, American neutrality softened. The Cash and Carry Act of November 1939 allowed warring nations to purchase American weapons if they paid in cash and transported them in their own ships. By March 1941, the Lend-Lease Act further expanded U.S. support, enabling the President to provide defense materials to friendly nations such as Britain and China. After Germany attacked the Soviet Union in June 1941, the USSR also became eligible for aid under this act.
The Turning Point: Germany’s Betrayal
The Soviet-German Non-Aggression Pact had been a strategic ploy by Hitler to keep the Soviet Union unaware of his plans for invasion. After defeating its European enemies, Germany turned its focus eastward. Despite warnings from Winston Churchill, the American Embassy, and even Soviet intelligence, Stalin refused to believe Hitler would attack. This illusion was shattered on June 22, 1941, when Germany launched its invasion of the USSR.
Caught off guard, the Soviet Union sought allied support. Britain promptly accepted the USSR into the Allied camp, signing a military pact in July 1941. As the Soviet Union fought a devastating war on its own soil, the United States was drawn into the conflict after Japan attacked Pearl Harbor on December 7, 1941.
U.S. Entry into the War
American-Japanese relations had been strained for years. The U.S. had frozen Japanese assets and warned against Japanese aggression in Southeast Asia. In August 1941, the U.S. declared that any Japanese attack on Thailand would be of grave concern. Efforts to mediate tensions failed. In September, U.S. President Franklin D. Roosevelt attempted to meet with Japanese Prime Minister Prince Konoe, but Konoe resigned in October and was replaced by General Hideki Tojo, who openly encouraged conflict.
As tensions escalated, Britain promised to declare war on Japan if the U.S. became involved. On December 6, 1941, Roosevelt made a personal appeal to the Japanese Emperor for peace. The next day, Japan bombed the U.S. naval base at Pearl Harbor in Hawaii. Shortly afterward, Japan declared war on the United States and Britain. On December 11, Germany and Italy followed suit, declaring war on the U.S., marking the global expansion of the war.
Thus, the United States and the Soviet Union became key allies in the fight against the Axis powers, forging an unlikely but crucial partnership during World War II.
Consequences of World War-II
The defeat of the Axis Powers—Italy, Germany, and Japan—marked the conclusion of World War II. While the detailed accounts of battles, victories, and defeats are beyond the scope of this overview, the key events that led to their collapse are summarized below.
Germany and Italy’s Defeat
At their peak, Germany and Italy had conquered vast swathes of Europe. England faced relentless attacks, and significant parts of the Soviet Union, including the three Baltic Republics, were under German occupation. However, by 1943, the Allies launched a counteroffensive aimed at dismantling the Axis grip on Europe.
The Fall of Italy
The Allies began their assault on the Axis by targeting Italian-held territories in Africa, achieving victory by May 1943. This marked the beginning of cracks in the Fascist regime. The Allies then initiated “Operation Husky,” an invasion of Sicily, in July 1943. After heavy airstrikes, Italian forces surrendered en masse. German troops failed to defend the island, and Mussolini sought Hitler’s assistance, which was denied.
Following these setbacks, Mussolini convened a meeting of the Fascist Grand Council, which urged King Victor Emmanuel III to take direct control. On July 25, 1943, the King dismissed Mussolini, appointed Marshal Pietro Badoglio to lead a new government, and had Mussolini arrested. Italy officially surrendered on September 3, 1943, but German forces swiftly occupied Rome, holding it until June 4, 1944, when the Allies liberated the city.
The Fall of Germany
The Allies planned to defeat Germany by opening two fronts. The Soviet Union pushed from the east, while the United States and its Western Allies advanced from the west. By March 1944, Axis forces were driven out of much of Ukraine and other parts of the Soviet Union. The Soviets cleared German troops from their soil by the end of 1944.
The Western Allies opened a second front on June 6, 1944, with the Normandy invasion, known as D-Day. Over 150,000 American troops crossed the English Channel in a massive operation. Within 97 days, Allied forces liberated France and advanced into Germany on September 11, 1944.
Despite the worsening situation, Hitler’s forces launched a massive bombardment of London, which persisted until early 1945. Meanwhile, internal conspiracies to assassinate Hitler emerged as Germany’s defeat became inevitable.
At the Yalta Conference in February 1945, the Allies coordinated their final assault on Germany. Soviet forces launched an unrelenting offensive, while British, Canadian, French, and American troops advanced from the west. The fiercest battles took place around the German Chancellery, where Hitler had established his final headquarters.
On April 30, 1945, realizing all was lost, Hitler committed suicide in his underground bunker. His designated successor, Admiral Karl Dönitz, was powerless to salvage the situation.
Germany’s Surrender
On May 5, 1945, German forces in Northeast Germany, the Netherlands, and Denmark surrendered. The following day, Nazi troops in Austria capitulated. Finally, on May 7, 1945, the Dönitz administration surrendered all German land, sea, and air forces unconditionally.
The war in Europe officially ended on May 8, 1945, marking Victory in Europe (V-E) Day. This historic day symbolized the collapse of the Axis Powers and the triumph of the Allies in Europe.
Defeat of Japan
In the Far East, the Allies made significant efforts to secure Japan’s defeat. The United States played a leading role, supported by Britain, China, the Netherlands, Australia, and New Zealand. China served as the base for coordinating Allied operations against Japan, with General Douglas MacArthur overseeing these efforts.
Allied Campaigns Against Japan
Two major Allied campaigns were launched in the fall of 1944:
- The Burma Campaign: Led by Lord Mountbatten, this campaign aimed to reconquer Burma, a key region under Japanese control.
- The Philippines Liberation: General MacArthur spearheaded this campaign to free the Philippine Islands from Japanese occupation.
Both missions were successfully completed by June 1945, though the intricate details of these operations are beyond the scope of this summary.
The Potsdam Declaration and Japan’s Refusal
In July 1945, the Allies, meeting at the Potsdam Conference to decide the future of defeated Germany and other war-related issues, issued an ultimatum to Japan. The Potsdam Declaration demanded Japan’s unconditional surrender, warning that refusal would result in “immediate and utter destruction.”
Japan, still at war with the Soviet Union and unwilling to surrender, rejected the ultimatum and continued fighting.
The Use of Atomic Bombs
Faced with Japan’s refusal, the United States made the unprecedented decision to use atomic weapons to force an unconditional surrender.
- Hiroshima: On August 6, 1945, the U.S. Air Force dropped the first atomic bomb on Hiroshima, destroying over half the city and causing massive casualties.
- Soviet Offensive: On August 8, 1945, the Soviet Union declared war on Japan, launching an aggressive campaign in Manchuria and Southern Sakhalin, both under Japanese control. Soviet forces advanced rapidly.
- Nagasaki: On August 9, 1945, the U.S. dropped a second atomic bomb on Nagasaki, resulting in unprecedented destruction.
Japan’s Surrender
The devastation from the atomic bombings and the Soviet advance forced Japan to seek peace. On August 10, 1945, Japan agreed to surrender. However, the formal surrender documents were signed later, on September 2, 1945, aboard the U.S. battleship Missouri.
This marked the official end of World War II, with Japan falling under American occupation.
The war concluded with the total defeat of the three Axis powers—Germany, Italy, and Japan—and the triumph of the Allies. It symbolized the victory of democracy over dictatorship and brought an end to one of the most devastating conflicts in human history.
Peace-Making After the Second World War
The conclusion of armistices following World War II proved to be a complex and prolonged process. Formal peace treaties were signed with five defeated nations—Italy, Romania, Bulgaria, Hungary, and Finland—only two years after the war ended. Peace agreements with Austria and Japan followed much later in 1955 and 1952, respectively. However, a unified Germany remained elusive. Germany was divided into the pro-West Federal Republic of Germany (West Germany) and the Democratic German Republic (East Germany) under Soviet influence. A formal peace settlement with Germany never materialized, and reunification was only achieved in 1990.
The post-war peace process also involved the Potsdam Conference, which laid the groundwork for treaties and the management of defeated powers.
The Potsdam Conference
The Potsdam Conference took place in July and August 1945 in Berlin, shortly after Germany’s unconditional surrender. The Allied leaders—Joseph Stalin (Soviet Union), Winston Churchill (later replaced by Clement Attlee, UK), Harry Truman (USA), and Chiang Kai-shek (China)—met to finalize decisions regarding Germany and other East European nations.
Key decisions and principles emerged from the conference, addressing Germany’s governance, punishment for war crimes, and disarmament.
Key Outcomes of the Potsdam Conference
Germany
- Disarmament: Germany was to be completely disarmed, with all Nazi laws and organizations abolished.
- War Criminals: Nazi war criminals would be tried and punished.
- Democracy: A democratic government would be established in Germany, restoring individual rights and freedoms.
- Economic and Naval Redistribution: Principles for economic reparations, the division of Germany’s navy, and merchant fleets were outlined.
- Territorial Adjustments: Poland was to gain territories east of the Oder-Neisse Rivers, pending final border agreements.
Poland
- Democratic elections were to be held in Poland to ensure a free and fair political system.
Iran and Tangier
- Allied forces were to withdraw from Iran, and Tangier was declared an international zone.
Austria
- Austria was exempted from paying reparations.
Japan
- Demilitarization: Japan was to be disarmed, and imperialistic elements in its governance eliminated.
- Territorial Limits: Japanese sovereignty was restricted to its four major islands and a few smaller ones.
- War Criminals: Japanese war criminals would be tried and punished.
- Return of Occupied Lands: All territories occupied by Japan before and during the war were to be restored to their rightful owners.
The End of WWII
Despite the Potsdam Declaration’s terms for Japan’s surrender, the Japanese government initially refused to comply. This led to the United States’ decision to use atomic weapons without informing the Soviet Union:
- Hiroshima (August 6, 1945): The first atomic bomb was dropped, causing immense destruction.
- Nagasaki (August 9, 1945): A second atomic bomb was deployed, further devastating Japan.
On August 10, 1945, Japan unconditionally surrendered, and the war officially ended.
Aftermath
The use of atomic weapons by the United States without prior consultation with the Soviet Union became a significant factor in the emergence of the Cold War, marking a shift from wartime alliances to post-war tensions. The end of World War II thus laid the foundation for both peace settlements and new geopolitical conflicts in the years that followed.
Treaties of Peace: An Overview
Unlike the Paris Peace Conference of 1919, the post-World War II peace negotiations began with a Foreign Ministers meeting in London from September 11 to October 3, 1945. Significant disagreements arose between the Western powers and the Soviet Union, causing little progress during the London conference or the subsequent three meetings. During these sessions, draft agreements were prepared with five nations—Italy, Romania, Bulgaria, Hungary, and Finland—to finalize treaties. A 12-nation Paris Conference followed from July 29 to October 15, 1946. Finally, the treaties were approved by the Foreign Ministers Committee on December 12, 1946, in New York, and were subsequently signed between the Allies and the defeated powers.
The principal provisions of these peace treaties are summarized below:
Italy
Italy faced significant territorial losses under its treaty. France, Greece, and Yugoslavia acquired territories at Italy’s expense, while Trieste became an autonomous port under the governance of a UN Security Council-appointed official. Albania and Ethiopia regained their sovereignty. Italy forfeited its colonies in Libya, Somaliland, and Eritrea and saw its defense forces substantially reduced. Additionally, Italy was required to pay heavy reparations within seven years.
Romania
Romania’s treaty ceded Bessarabia and Bukovina to the Soviet Union and Dobruja to Bulgaria. The country was also obligated to compensate the Soviet Union and had its military capabilities curtailed.
Hungary
Hungary was required to return villages south of the Danube, occupied in 1938, to Czechoslovakia, and the Transylvania region was returned to Romania. Hungary’s military strength was limited, and it was ordered to pay reparations.
Bulgaria
Bulgaria retained its territory and even gained Dobruja from Romania. However, it was required to pay reparations and significantly reduce its armed forces.
Finland
Finland ceded territories such as the Salla region, Petsamo province, and the Porkkala Udd naval base to the Soviet Union. Like other defeated nations, Finland faced reparations and a reduction in military forces.
These treaties ultimately benefited the Soviet Union the most, expanding its territory, influence, and power. Yugoslavia also gained prominence, emerging as the dominant power in the Balkans and a rival to Italy.
Austria
Austria had been annexed by Germany in 1938 and remained under occupation as part of defeated Germany. Unlike Germany, Austria was treated as a liberated territory. The 1943 Moscow Conference had pledged Austria’s sovereignty, but post-war tensions between the Allies delayed resolution. The Soviet Union sought strict economic restrictions on Austria, which the Western powers opposed. A compromise was reached nearly a decade later when Austria declared neutrality and agreed to compensate the Soviet Union. On May 15, 1955, Austria signed a peace treaty and became a neutral nation.
Japan
The conclusion of peace with Japan was delayed due to the Cold War and disagreements between the United States and the Soviet Union. Unlike Germany and Austria, Japan was under exclusive American occupation following its surrender on August 10, 1945. General MacArthur, as Supreme Commander of the Allied Powers, led an interim military administration.
In 1951, the United States convened a peace conference in San Francisco, attended by 52 nations. The Soviet Union and other communist nations participated, but India and Burma declined. India disagreed with certain terms of the proposed treaty. Ultimately, 49 nations signed the US-drafted treaty with Japan on April 28, 1952. India signed a separate peace treaty with Japan in June 1952.
The treaty, comprising 27 articles, recognized Korea’s independence, marking a new chapter in Japan’s post-war recovery.
Emergence of Superpowers
The concept of superpowers emerged after World War II when the traditional great powers were eclipsed in influence by two nations: the United States and the Soviet Union. Before the war, global power dynamics included nations like the British Empire, France, Italy, and Japan. However, the war’s conclusion brought profound changes.
Germany, Italy, and Japan—key Axis powers—were decisively defeated. Germany was divided and occupied by four Allied nations, while Japan faced devastation from atomic bomb attacks. These defeated nations became militarily weakened, politically marginalized, and economically shattered.
Among the victorious Allied nations, Britain emerged severely weakened. By 1947, it could no longer maintain its troops in Greece and Turkey to resist communism. The British Empire, once a dominant global power, began to decline rapidly, with the decolonization process accelerating after India gained independence in 1947. Although Britain retained its status as a permanent member of the United Nations Security Council, its influence was significantly diminished.
France, too, faced a decline in power. It had been occupied by Germany until its liberation in August 1944 with the opening of a second front. Despite being one of the victors of World War II and securing a permanent seat on the Security Council, France remained weakened for several years after the war.
This left only two dominant powers: the United States and the Soviet Union. Both emerged from the war with enhanced military strength and elevated political influence. The United States benefited from its robust economy, technological advancements, and nuclear arsenal, while the Soviet Union expanded its influence across Eastern Europe and established itself as a military and ideological rival to the U.S.
Even as other nations—such as Britain, France, and China—later developed nuclear capabilities, they could not rival the superpower status of the U.S. and the USSR. The emergence of these two superpowers was one of the most significant outcomes of World War II, shaping the geopolitical landscape for decades to come.
The United States Becomes a Nuclear Power
At the end of World War II, the United States was the only nation with an unparalleled capability: nuclear weapons. In July 1945, the U.S. successfully tested the first atomic bomb in history. This breakthrough was followed by the deployment of two atomic bombs on Hiroshima and Nagasaki in August, which forced Japan’s unconditional surrender and brought the war to an end.
The U.S. kept its nuclear program secret, even from its wartime allies. The Soviet Union and the rest of the world were shocked when the bomb was used, as its development had not been disclosed. Even when the U.S. decided to use the atomic bomb on Japan, the Allied nations were not informed until after the bombs were dropped.
Japan’s surrender secured an American victory in the Pacific, leaving the Soviet Union with only a token role in the post-war settlement in the Far East. For the next five years, the U.S. maintained an unchallenged monopoly on nuclear weapons until the Soviet Union tested its own atomic bomb in 1949. During this time, tensions escalated as the Cold War began, with the West openly blaming the Soviet Union for the conflict. The possibility of the U.S. possessing additional atomic bombs created uncertainty and fear. As Peter Calvocoressi observed, the Soviet Union was vulnerable, knowing that if the U.S. had a third bomb, it could destroy Moscow or Leningrad just as it had Hiroshima and Nagasaki. While the U.S. may not have intended such actions, the threat solidified its position as the world’s preeminent power for at least five years.
America’s ascent as a superpower was not solely due to its nuclear arsenal. The country also benefited from being shielded from the devastation of war on its own soil. Apart from the attack on Pearl Harbor, the U.S. avoided the widespread destruction and civilian casualties that its allies endured. In contrast, the Soviet Union suffered immense losses from the German invasion, France endured occupation for four years, and Britain faced relentless bombardment.
Until the Soviet Union successfully tested its own nuclear device in 1949, the United States maintained an unchallenged dominance in nuclear capability. Even afterward, through 1953, the U.S. held a significant technological edge over the USSR in military and political power. Additionally, the U.S. boasted the world’s strongest air force and a leading navy. By the end of the war, both the U.S. and the USSR had approximately 12 million men in their armed forces, but America’s economic and technological superiority gave it a decisive advantage.
The Soviet Union’s Challenge to the United States
The Soviet Union’s power base was not initially comparable to that of the United States. While the Soviet Union successfully established communist regimes in Poland and other Eastern European nations liberated from Nazi rule, it lacked nuclear weapons until testing its first atomic device in 1949. Moreover, the USSR faced severe losses during World War II, including approximately 20 million fatalities, widespread civilian casualties, and significant military casualties.
Economically, the Soviet Union was far behind the United States. For instance, while U.S. steel production increased by 50% during the war, Soviet steel production was halved. Similarly, U.S. automobile production reached 7 million vehicles annually, whereas the Soviet Union produced only 65,000 vehicles per year.
Despite these economic disparities, the Soviet Union emerged as the second-most powerful nation in the world after World War II. Its influence extended over strategic territories, as Geir Lundestad notes: “The nation expanded its region extensively—annexing the Baltic states, Eastern Karelia, Petsamo, parts of pre-war Poland, northern East Prussia, Carpathian Ukraine, Bessarabia, northern Bukovina, Southern Sakhalin, and the Kurile Islands.”
The USSR became a nuclear power in 1949, which significantly elevated its status. Although the U.S. maintained superiority in areas such as nuclear delivery systems until 1953, the Soviet Union’s acquisition of nuclear weapons ensured its recognition as a superpower. The communist revolution in China in 1949 and the signing of a long-term treaty between the Soviet Union and China further boosted Soviet influence.
Post-war, the Soviet Union prioritized surpassing the United States in science and technology, channeling resources into military advancements. Once it achieved nuclear capability, the USSR emerged as a direct rival to the U.S., with both nations recognized as superpowers leading opposing ideological blocs.
The rivalry between the United States and the Soviet Union quickly manifested across various regions of the world. As Geir Lundestad observed: “They were the two main actors in the international arena. The geographic distance separating them had vanished, but the political distance between them would soon be greater than ever.” This political divide set the stage for the Cold War, with the U.S. and USSR locked in a global struggle for influence.
Conclusion
The Second World War began on September 1, 1939, when Nazi Germany invaded Poland. In response, Britain and France declared war on Germany two days later. Prior to this, Germany and the Soviet Union had signed a non-aggression pact, which was widely criticized as a covert agreement to divide Poland between the two nations.
The major causes of World War II included the Treaty of Versailles, which ended World War I but humiliated Germany and was regarded by many Germans as a “diktat” or unfair imposition. The failure of disarmament efforts, which were seen as critical to avoiding war, also played a role. The global economic crisis of the 1930s fueled militarism and aggressive actions in countries like Japan. Additionally, the formation of the Rome-Berlin-Tokyo Axis, a coalition of fascist powers intent on overthrowing the existing world order, heightened tensions. Other contributing factors included the failure to address minority grievances, the policy of appeasement adopted by Britain and France to placate fascist dictators, and, ultimately, Germany’s invasion of Poland, which directly triggered the conflict.
Initially, several nations joined the war on the side of Britain and her allies, but the United States remained neutral until Japan’s surprise attack on Pearl Harbor in December 1941 forced it into the war. Meanwhile, the Soviet Union, having invaded Poland and Finland, was expelled from the League of Nations. However, when Germany betrayed the non-aggression pact and attacked the Soviet Union in June 1941, the Soviets joined Britain as allies.
Italy entered the war in June 1940, allying with Germany and declaring war on France. However, the Axis powers suffered their first significant setback in 1943 when Italy was invaded. Mussolini was dismissed, and Italy surrendered, although Rome remained under German control for some time. The Soviet Union fought fiercely to liberate Eastern Europe, while the Allies, led by the United Kingdom and the United States, opened a second front, leading to the liberation of France and Germany’s eventual surrender in May 1945. Japan continued fighting in the Pacific until August 1945, when the United States dropped two atomic bombs on Hiroshima and Nagasaki, forcing Japan’s surrender and ending the war.
The defeat of the Axis powers marked a victory for the Allies but left the world with significant challenges. Efforts to establish peace proved difficult. The Potsdam Conference of 1945 aimed to negotiate a peace treaty with Germany, but no immediate agreement was reached. Peace treaties with Italy, Romania, Hungary, and Finland were concluded only after prolonged negotiations, while treaties with Japan and Austria followed later. Due to Germany’s occupation, no formal peace treaty was signed for several years.
One of the most significant outcomes of the war was the division of Germany into four occupation zones controlled by the Allied powers. Over time, the three Western zones merged to form a sovereign nation, while the Soviet Union established a socialist government in the eastern zone. As the Soviet army liberated Eastern Europe, communist regimes were installed, leading to the emergence of a divided world and the onset of the Cold War.
The war devastated most major powers, but the United States emerged relatively unscathed, as no battles were fought on its territory, and civilian casualties were minimal. The U.S. became the first country to develop and use nuclear weapons, while the Soviet Union acquired similar capabilities five years later. With other major powers significantly weakened, the United States and the Soviet Union emerged as the two dominant superpowers, each leading opposing ideological blocs in a polarized global order.
References
- Langsam, W.C. and Mitchell, The World Since 1919, New York: Macmillan Publishing Co.
- Albrecht, Carrie, A Diplomatic History of Europe Since the Congress of Vienna, New York: Harper and Row.
- Johnson, Paul, A History of the Modern World from 1917 to the 1980s, London: Weidenfeld and Nicolson.
- Dhar, S.N., International Relations and World Politics Since 1919, New Delhi: Kalyani Publishers.