WW2

World War II

Introduction

• The global war that lasted from 1939 to 1945
• Involved the majority of the world's nations, including all of the great powers
• Fought in two significant theaters: Europe and Asia-Pacific
• This resulted in the deaths of an estimated 70-85 million people

Causes

• The Treaty of Versailles (1919) imposed harsh penalties on Germany after World War I
• Rise of fascist regimes in Europe, including Nazi Germany under Adolf Hitler
• Failure of appeasement policy by Western powers
• Invasion of Poland by Germany in 1939

Major Events

• Invasion of Poland (1939)
• Battle of Britain (1940)
• Operation Barbarossa (1941)
• Pearl Harbor (1941)
• Battle of Stalingrad (1942-43)
• D-Day (1944)
• Atomic bombings of Hiroshima and Nagasaki (1945)

Major Powers

• Allies: United States, United Kingdom, Soviet Union, France, China
• Axis: Germany, Japan, Italy

Consequences

• Formation of the United Nations
• Establishment of the Cold War between the Western powers and the Soviet Union
• Decolonization of Africa and Asia
• The emergence of the United States and the Soviet Union as superpowers

Conclusion

• World War II was a catastrophic event that profoundly impacted the world.
• It resulted in significant changes to the global political and economic landscape.
• It serves as a reminder of the devastating consequences of war and the importance of international cooperation and diplomacy.

Dates: 1939-1945

Countries involved: Germany, Japan, Italy, United States, United Kingdom, Soviet Union, France, and many others

Causes: Treaty of Versailles, the rise of fascist regimes, appeasement policies, and territorial disputes

Significant events: Invasion of Poland, Battle of Stalingrad, D-Day, Battle of Midway, Atomic bombings of Hiroshima and Nagasaki

Casualties: Estimated 70-85 million fatalities, including 6 million Jews, in the Holocaust

Consequences: Formation of the United Nations, Cold War, decolonization, and the establishment of Israel.

World War II was a catastrophic conflict with far-reaching consequences that affected the entire world. It began on September 1, 1939, when Nazi Germany invaded Poland, prompting Britain and France to respond. The war rapidly spread, involving most of the world's nations. The two opposing military alliances were the Allies, which included the United States, Britain, France, and the Soviet Union, and the Axis, Germany, Italy, and Japan.

The war saw the mobilization of over 100 million military personnel, including soldiers, sailors, and airmen, and was fought on multiple fronts, including Europe, Africa, Asia, and the Pacific. The conflict was characterized by brutal battles, such as the Battle of Stalingrad and the Normandy landings, which resulted in significant loss of life and destruction.

The primary causes of the war were the aggressive actions of Nazi Germany, led by Adolf Hitler, and the expansionist policies of Imperial Japan. Hitler aimed to expand Germany's territory and create a "New Order" in Europe, while Japan sought to establish dominance in Asia and the Pacific. These aggressive actions led to the invasion of Poland and Britain and France's subsequent declaration of war.

The war had a profound impact on the world, resulting in the death of millions of people and the displacement of millions more. It also led to the formation of the United Nations and establishment of international laws and norms to prevent future conflicts. The war ended with Germany's unconditional surrender on May 8, 1945, and the dropping of atomic bombs on the Japanese cities of Hiroshima and Nagasaki, leading to Japan's surrender on August 15, 1945.

In conclusion, World War II was a global conflict that significantly impacted the world. It involved mobilizing millions of military personnel, resulting in significant loss of life and destruction. The primary causes of the war were the aggressive actions of Nazi Germany and Imperial Japan. The war ended with the defeat of the Axis powers and the establishment of a new world order.

• It is generally considered that, in Europe, World War II started on September 1, 1939,[3] beginning with the German invasion of Poland and the United Kingdom and France's declaration of war on Germany two days later on September 3, 1939. Others view the Spanish Civil War as the start or prelude to World War II.[11][12]The exact date of the war's end is also not universally agreed upon. It was generally accepted at the time that the war ended with the armistice of August 14, 1945 (V-J Day) rather than with the formal surrender of Japan on September 2, 1945, which officially ended the war in Asia. A peace treaty between Japan and the Allies was signed in 1951. A 1990 treaty regarding Germany's future allowed the reunification of East and West Germany and resolved most post–World War II issues.[14] No formal peace treaty between Japan and the Soviet Union was ever signed [15]. However, the state of war between the two countries was terminated by the Soviet–Japanese Joint Declaration of 1956, restoring full diplomatic relations between them.[16]

• The aftermath of World War I

  World War I radically altered the European political map with the defeat of the Central Powers—including Austria-Hungary, Germany, Bulgaria, and the Ottoman Empire—and the 1917 Bolshevik seizure of power in Russia, which led to the founding of the Soviet Union. The League of Nations was created during the 1919 Paris Peace Conference to prevent a future world war. The organization's primary goals were to prevent armed conflict through collective security, military and naval disarmament, and settling international disputes through peaceful negotiations and arbitration.[17]Despite strong pacifist sentiment after World War I, irredentist and revanchist nationalism emerged in several European states in the same period. These sentiments were especially marked in Germany because of the significant territorial, colonial, and financial losses imposed by the Treaty of Versailles. Under the treaty, Germany lost around 13 percent of its home territory and all its overseas possessions. At the same time, the German annexation of other states was prohibited, reparations were imposed, and limits were placed on the size and capability of the country's armed forces.

• Germany

  The German Empire was dissolved in the German Revolution of 1918–1919, and a democratic government, later known as the Weimar Republic, was created. The interwar period saw strife between supporters of the new republic and hardline opponents on both the right and left. From 1922 to 1925, the Fascist movement led by Benito Mussolini seized power in Italy with a nationalist, totalitarian, and class collaborationist agenda that abolished representative democracy and repressed socialist, left-wing, and liberal forces. It pursued an aggressive expansionist foreign policy aimed at making Italy a world power and promising the creation of a "New Roman Empire" After an unsuccessful attempt to overthrow the German government in 1923, Adolf Hitler eventually became the Chancellor of Germany in 1933 when Paul Von Hindenburg and the Reichstag appointed him. Meanwhile, to secure its alliance, France allowed Italy a free hand in Ethiopia, which Italy desired as a colonial possession.

• European treaties

  The United Kingdom, France, and Italy formed the Stresa Front in April 1935 to contain Germany, a critical step towards military globalization; however, that June, the United Kingdom made an independent naval agreement with Germany, easing prior restrictions. The Soviet Union, concerned by Germany's goals of capturing vast areas of Eastern Europe, drafted a mutual assistance treaty with France. Hitler defied the Versailles and Locarno Treaties by remilitarizing the Rhineland in March 1936, encountering little opposition due to the policy of appeasement. In October 1936, Germany and Italy formed the Rome–Berlin Axis. A month later, Germany and Japan signed the Anti-Comintern Pact, which Italy joined the following year.

• Asia

  The Kuomintang (KMT) party in China launched a unification campaign against regional warlords and nominally unified China in the mid-1920s. However, it was soon embroiled in a civil war against its former Chinese Communist Party allies and new regional warlords. In 1931, an increasingly aggressive Empire of Japan, which had long sought influence in China as the first step of what its government saw as the country's right to rule Asia, staged the Mukden Incident as a pretext to invade Manchuria and establish the puppet state of Manchukuo. China appealed to the League of Nations to stop the Japanese invasion of Manchuria. Japan withdrew from the League of Nations after being condemned for its incursion into Manchuria. The two nations then fought several battles in Shanghai, Rehe, and Hebei until the Tanggu Truce was signed in 1933.

• The Italian Invasion of Ethiopia (1935)

  The Second Italo-Ethiopian War was a brief colonial war that began in October 1935 and ended in May 1936. The battle started with the invasion of the Ethiopian Empire (also known as Abyssinia) by the armed forces of the Kingdom of Italy (Regno d'Italia), which was launched from Italian Somaliland and Eritrea.[32] The war resulted in the military occupation of Ethiopia and its annexation into the newly created colony of Italian East Africa (Africa Orientale Italiana, or AOI); it also exposed the weakness of the League of Nations as a force to preserve peace. Italy and Ethiopia were member nations, but the League did little when the former violated Article X of the League's Covenant. The United Kingdom and France supported imposing sanctions on Italy for the invasion, but the sanctions were not fully enforced and failed to end the Italian invasion. Italy subsequently dropped its objections to Germany's goal of absorbing Austria.

• Spanish Civil War (1936–1939)

  When civil war broke out in Spain, Hitler and Mussolini lent military support to the Nationalist rebels led by General Francisco Franco. Italy supported the Nationalists to a greater extent than the Nazis did: altogether, Mussolini sent more than 70,000 ground troops and 6,000 aviation personnel, and about 720 aircraft to Spain. The Soviet Union supported the existing government of the Spanish Republic. Both Germany and the Soviet Union used this proxy war as an opportunity to test in combat their most advanced weapons and tactics. His most significant collaboration with Germany was sending volunteers to fight on the Eastern Front.

• The Japanese Invasion of China (1937)

  In July 1937, Japan captured the former Chinese imperial capital of Peking after instigating the Marco Polo Bridge Incident, culminating in the Japanese campaign to invade all of China. The Soviets quickly signed a non-aggression pact with China to lend materiel support, effectively ending China's prior cooperation with Germany. From September to November, the Japanese attacked Taiyuan, engaged the Kuomintang Army around Xinkou,[40][unreliable source?] and fought Communist forces in Pingxingguan.[41][42] Generalissimo Chiang Kai-shek deployed his best army to defend Shanghai, but after three months of fighting, Shanghai fell. The Japanese continued to push the Chinese forces back, capturing the capital Nanking in December 1937. In June 1938, Chinese forces stalled the Japanese advance by flooding the Yellow River; this maneuver bought time for the Chinese to prepare their defenses at Wuhan, but the city was taken by October.

• Soviet–Japanese border conflicts

  In the mid-to-late 1930s, Japanese forces in Manchukuo had sporadic border clashes with the Soviet Union and Mongolia. The Japanese doctrine of Hokushin-ron, which emphasized Japan's expansion northward, was favored by the Imperial Army during this time. With the Japanese defeat at Khalkin Gol in 1939, the ongoing Second Sino-Japanese War, and ally Nazi Germany pursuing neutrality with the Soviets, this policy would prove difficult to maintain. Japan and the Soviet Union eventually signed a Neutrality Pact in April 1941. Japan adopted the doctrine of Nanshin-ron, promoted by the Navy, which took its focus southward, eventually leading to its war with the United States and the Western Allies.[50][51]

• European Occupations and Agreements

  In Europe, Germany and Italy were becoming more aggressive. In March 1939, Germany invaded the remainder of Czechoslovakia and split it into the German Protectorate of Bohemia and Moravia and a pro-German client state, the Slovak Republic. Greatly alarmed and with Hitler making further demands on the Free City of Danzig, the United Kingdom, and France guaranteed their support for Polish independence; when Italy conquered Albania in April 1939, the same guarantee was extended to the Kingdoms of Romania and Greece. The situation reached a general crisis in late August as German troops mobilized against the Polish border. On August 23, when tripartite negotiations about a military alliance between France, the United Kingdom, and the Soviet Union stalled,[60] the Soviet Union signed a non-aggression pact with Germany.

• War breaks out in Europe (1939–1940)

  Soldiers of the German Wehrmacht tearing down the border crossing into Poland, September 1 1939On September 1, 1939, Germany invaded Poland after having staged several false flag border incidents as a pretext to initiate the invasion. A significant part of Polish military personnel evacuated to Romania and Latvia; many later fought against the Axis in other theatres of the war. On October 6, Hitler made a public peace overture to the United Kingdom and France but said that the future of Poland was to be determined exclusively by Germany and the Soviet Union. The proposal was rejected,[65] and Hitler ordered an immediate offensive against France,[76] which was postponed until the spring of 1940 due to bad weather.[79]After the outbreak of war in Poland, Stalin threatened Estonia, Latvia, and Lithuania with military invasion, forcing the three Baltic countries to sign pacts that stipulated the creation of Soviet military bases in these countries. Finland refused to sign a similar deal and rejected ceding part of its territory to the Soviet Union. In June 1940, the Soviet Union occupied Estonia, Latvia, and Lithuania territories, the Romanian regions of Bessarabia, Northern Bukovina, and the Hertsa region.

• Western Europe (1940–1941)

  The German advance into Belgium and Northern France, May 10 – June 4, 1940, swept past the Maginot Line (shown in dark red). In April 1940, Germany invaded Denmark and Norway to protect iron ore shipments from Sweden, which the Allies attempted to cut off.[95] Denmark capitulated after six hours, and Norway was conquered within two months despite Allied support. On the same day, Germany launched an offensive against France. By implementing new Blitzkrieg tactics, the Wehrmacht rapidly advanced to the Channel and cut off the Allied forces in Belgium, trapping the bulk of the Allied armies in a cauldron on the Franco-Belgian border near Lille. France kept its fleet, which the United Kingdom attacked on July 3, to prevent its seizure by Germany. The air Battle of Britain began in early July with Luftwaffe attacks on shipping and harbors.[107] The United Kingdom rejected Hitler's peace offer [108]. The German air superiority campaign started in August but failed to defeat RAF Fighter Command, forcing the indefinite postponement of the proposed German invasion of Britain. Romania and Hungary later made significant contributions to the Axis war against the Soviet Union, in Romania's case partially to recapture territory ceded to the Soviet Union.

• Mediterranean (1940–1941)

  In early June 1940, the Italian Regia Aeronautica attacked and besieged Malta, a British possession. The Italian Navy also suffered significant defeats. The Royal Navy put three Italian battleships out of commission using a carrier attack at Taranto and neutralizing several more warships at the Battle of Cape Matapan. Italian defeats prompted Germany to deploy an expeditionary force to North Africa, and at the end of March 1941, Rommel's Afrika Korps launched an offensive that drove back the Commonwealth forces. The airborne invasion of the Greek island of Crete at the end of May completed the German conquest of the Balkans. Although the Axis victory was swift, bitter, and large-scale partisan warfare subsequently broke out against the Axis occupation of Yugoslavia, which continued until the war's end. Between June and July, British-led forces invaded and occupied the French possessions of Syria and Lebanon, assisted by the Free French.[129]

• Axis attack on the Soviet Union (1941)

  With the situation in Europe and Asia relatively stable, Germany, Japan, and the Soviet Union prepared for war. On July 31, 1940, Hitler decided that the Soviet Union should be eliminated and aimed for the conquest of Ukraine, the Baltic states, and Byelorussia.[133] However, other senior German officials like Ribbentrop saw an opportunity to create a Euro-Asian bloc against the British Empire by inviting the Soviet Union into the Tripartite Pact.[134] In November 1940, negotiations took place to determine if the Soviet Union would join the pact. Although the Red Army was preparing for strategic counter-offensives before the war, Operation Barbarossa forced the Soviet supreme command to adopt a strategic defense. The Kyiv offensive was overwhelmingly successful, resulting in the encirclement and elimination of four Soviet armies, and made possible further advance into Crimea and industrially developed Eastern Ukraine (the First Battle of Kharkiv). In July, the UK and the Soviet Union formed a military alliance against Germany. In August, the United Kingdom and the United States jointly issued the Atlantic Charter, which outlined British and American goals for the post-war world. The blitzkrieg phase of the war in Europe had ended.

• War breaks out in the Pacific (1941)

  Following the false Japanese flag Mukden Incident in 1931, the Japanese shelling of the American gunboat USS Panay in 1937, and the 1937–38 Nanjing Massacre, Japanese-American relations deteriorated. Chinese nationalist forces launched a large-scale counter-offensive in early 1940. In August, Chinese communists launched an offensive in Central China; in retaliation, Japan instituted harsh measures in occupied areas to reduce human and material resources for the communists. The Dutch government agreed to provide Japan with oil supplies from the Dutch East Indies, but negotiations for additional access to their resources failedfailed in June 1941.[166] In July 1941, Japan sent troops to southern Indochina, thus threatening British and Dutch possessions in the Far East. It called for the end of American aid to China and lifted the embargo on oil and other resources supplied to Japan. Japan planned to seize European colonies in Asia to create a large defensive perimeter stretching into the Central Pacific.

• Axis advance stalls (1942–1943)

  On January 1, 1942, the Allied Big Four —the Soviet Union, China, the United Kingdom, and the United States—and 22 smaller or exiled governments issued the Declaration by United Nations, thereby affirming the Atlantic Charter and agreeing not to sign a separate peace with the Axis powers. All decided that defeating Germany was the primary objective. The Americans favored a direct, large-scale attack on Germany through France. The Soviets were also demanding a second front. Germany itself would be subject to a heavy bombing campaign. An offensive against Germany would then be launched primarily by Allied armor without using large-scale armies.[194] Eventually, the British persuaded the Americans that a landing in France was infeasible in 1942 and that they should focus on driving the Axis out of North Africa.[195]At the Casablanca Conference in early 1943, the Allies reiterated the statements issued in the 1942 Declaration and demanded the unconditional surrender of their enemies.

• Pacific (1942–1943)

  Map of Japanese military advances through mid-1942By the end of April 1942, Japan and its ally Thailand had almost fully conquered Burma, Malaya, the Dutch East Indies, Singapore, and Rabaul, inflicting severe losses on Allied troops and taking a large number of prisoners. These easy victories over the unprepared U.S. and European opponents left Japan overconfident and overextended. In early May 1942, Japan initiated operations to capture Port Moresby by amphibious assault, thus severing communications and supply lines between the United States and Australia. In early June, Japan put its operations into action. Still, the Americans, having broken Japanese naval codes in late May, were fully aware of the plans and order of battle and used this knowledge to achieve a decisive victory at Midway over the Imperial Japanese Navy.[208]With its capacity for aggressive action significantly diminished due to the Midway battle, Japan focused on a belated attempt to capture Port Moresby by an overland campaign in the Territory of Papua. In Burma, Commonwealth forces mounted two operations. The first, an offensive into the Arakan region in late 1942, went disastrously, forcing a retreat back to India by May 1943.

• Eastern Front (1942–1943)

  Despite considerable losses, in early 1942, Germany and its allies stopped a major Soviet offensive in central and southern Russia, keeping most territorial gains they had achieved during the previous year. The Germans split Army Group South into two groups: Army Group A advanced to the lower Don River and struck southeast to the Caucasus, while Army Group B headed towards the Volga River. The Soviets decided to make their stand at Stalingrad on the Volga. By mid-November, the Germans had nearly taken Stalingrad in bitter street fighting. In mid-February, after the Soviet push had tapered off, the Germans launched another attack on Kharkiv, creating a salient in their front line around the Soviet city of Kursk.

• Western Europe/Atlantic and Mediterranean (1942–1943)

  The German navy ravaged Allied shipping off the American Atlantic coast by exploiting poor American naval command decisions. In North Africa, the Germans launched an offensive in January, pushing the British back to positions at the Gazala line by early February, followed by a temporary lull in combat which Germany used to prepare for their upcoming offensives. Concerns the Japanese might use bases in Vichy-held Madagascar caused the British to invade the island in early May 1942. An Axis offensive in Libya forced an Allied retreat deep inside Egypt until Axis forces were stopped at El Alamein. On the Continent, raids of Allied commandos on strategic targets, culminating in the disastrous Dieppe Raid, demonstrated the Western Allies' inability to launch an invasion of continental Europe without much better preparation, equipment, and operational security.[page needed]In August 1942, the Allies succeeded in repelling a second attack against El Alamein and, at a high cost, delivered desperately needed supplies to the besieged Malta.

• Allies gain momentum (1943–1944)

  After the Guadalcanal campaign, the Allies initiated several operations against Japan in the Pacific. In May 1943, Canadian and U.S. forces were sent to eliminate Japanese forces from the Aleutians. On July 5, 1943, Germany attacked Soviet forces around the Kursk Bulge. On September 3, 1943, the Western Allies invaded the Italian mainland, following Italy's armistice with the Allies and the ensuing German occupation of Italy.[248] Germany, with the help of fascists, responded to the truce by disarming Italian forces in many places without superior orders, seizing military control of Italian areas, and creating a series of defensive lines. German operations in the Atlantic also suffered.

• Allies closed in (1944)

  On June 6, 1944 (known as D-Day), after three years of Soviet pressure,[271] the Western Allies invaded northern France. After reassigning several Allied divisions from Italy, they also attacked southern France.[272] These landings were successful and led to the defeat of the German Army units in France. Allied advance slowed in Italy due to the last central German defensive line.[275]On June 22, the Soviets launched a strategic offensive in Belarus ("Operation Bagration"), almost destroying the German Army Group Centre.[276] Soon after, another Soviet strategic offensive forced German troops from Western Ukraine and Eastern Poland. By the start of July 1944, Commonwealth forces in Southeast Asia had repelled the Japanese sieges in Assam, pushing the Japanese back to the Chindwin River[284] while the Chinese captured Myitkyina. In mid-June 1944, they began their offensive against the Mariana and Palau islands and decisively defeated Japanese forces in the Battle of the Philippine Sea. These defeats led to the resignation of the Japanese Prime Minister, Hideki Tojo. They provided the United States with air bases to launch intensive heavy bomber attacks on the Japanese home islands.

• Axis collapse and Allied victory (1944–1945)

  In mid-January 1945, the Red Army attacked Poland, pushing from the Vistula to the Oder River in Germany, and overran East Prussia.[291] On February 4, Soviet, British, and U.S. leaders met for the Yalta Conference. On April 30, the Reichstag was captured, signaling the military defeat of Nazi Germany,[295] and the Berlin garrison surrendered on May 2. Major leadership changes occurred on both sides during this period. On April 12, President Roosevelt died and was succeeded by his vice president, Harry S. Truman. They landed in Luzon in January 1945 and recaptured Manila in March. American naval and amphibious forces also moved towards Japan, taking Iwo Jima by March and Okinawa by the end of June.[302] At the same time, a naval blockade by submarines was strangling Japan's economy and drastically reducing its ability to supply overseas forces.[303][304]On July 11, Allied leaders met in Potsdam, Germany.

• Aftermath

  The Allies established occupation administrations in Austria and Germany, initially divided between western and eastern occupation zones controlled by the Western Allies and the Soviet Union. By the 1950s, one-fifth of West Germans were refugees from the East. The alliance between the Western Allies and the Soviet Union had deteriorated even before the war.[329]Germany had been de facto divided, and two independent states, the Federal Republic of Germany (West Germany) and the German Democratic Republic (East Germany) [330], were created within the borders of Allied and Soviet occupation zones. As a result, East Germany,[332] Poland, Hungary, Romania, Bulgaria, Czechoslovakia, and Albania[333] became Soviet satellite states. Communist forces were victorious and established the People's Republic of China on the mainland, while nationalist forces retreated to Taiwan in 1949.[339] In the Middle East, the Arab rejection of the United Nations Partition Plan for Palestine and the creation of Israel marked the escalation of the Arab–Israeli conflict. The agreement created the International Monetary Fund (IMF) and the International Bank for Reconstruction and Development (IBRD).

• Casualties and war crimes

  World War II deathsEstimates for the total number of casualties in the war vary because many deaths went unrecorded.[359] Most suggest that 60 million people died in the war, including about 20 million military personnel and 40 million civilians.[360][361][362]Many of the civilians died because of deliberate genocide, massacres, mass bombings, disease, and starvation. General Yasuji Okamura implemented the policy in Heipei and Shantung.[382]Axis forces employed biological and chemical weapons.

• Genocide, concentration camps, and slave labor

  After 1942, the number reached 10 million.[408] In Java, between 4 and 10 million rōmusha (Japanese: "manual laborers") were forced to work by the Japanese military. About 270,000 Javanese laborers were sent to other Japanese-held areas in Southeast Asia, and only 52,000 were repatriated to Java.[409]

• Occupation

  In Europe, occupation came under two forms.

• Home fronts and production

  Allies to Axis GDP ratio between 1938 and 1945In Europe, before the outbreak of the war, the Allies had significant advantages in population and economics. To the Allies having more access to natural resources, other factors, such as Germany and Japan's reluctance to employ women in the labor force,[421] Allied strategic bombing,[422] and Germany's late shift to a war economy[423], contributed significantly. Neither Germany nor Japan planned to fight a protracted war and had not equipped themselves to do so.[424] To improve their production, Germany and Japan used millions of slave laborers;[425] Germany used about 12 million people, mostly from Eastern Europe,[401] while Japan used more than 18 million people in Far East Asia.[408][409]

• Advances in technology and its application

  Aircraft were used for surveillance, as fighters, bombers, and ground support, and each role developed considerably. Innovations included airlift (the capability to move limited high-priority supplies, equipment, and personnel quickly);[426] and strategic bombing (the bombing of enemy industrial and population centers to destroy the enemy's ability to wage war).[427] Anti-aircraft weaponry also advanced, including defenses such as radar and surface-to-air artillery. The use of the jet aircraft was pioneered, and though late introduction meant it had little impact, it led to jets becoming standard in air forces worldwide.[428]Advances were made in nearly every aspect of naval warfare, most notably with aircraft carriers and submarines