Many of the unresolved issues at the end of the first World War were instrumental in causing the even more devastating second World War. These conflicts were accentuated by the ideological extremism of the 1920s and 1930s, when totalitarian states sought to centralize their societies and expand their domain without regard for diplomacy or human rights. The main arenas of the war were in eastern Europe and western Russia, as well as in China and the adjacent lands of eastern Asia. Peripheral combat zones popped up in western and southern Europe, North Africa, and the island systems of the central and southwest Pacific Ocean.
From 1939 to 1942, the triumph of Nazi Germany was almost entirely unchecked. The Germans took control of most of eastern and northern Europe with few casualties. After the fall of France, only Britain was left to defend itself against invasion, all while fighting to keep open its sea lanes to America and the British Empire. Repelled by British air and sea power, Hitler in 1941 turned his attention to the Mediterranean and then to his proclaimed enemy, the Soviet Union. After helping his weaker ally Italy to invade the Balkans and North Africa, he launched a massive invasion of the U.S.S.R., which nearly reached Moscow before winter set in. 1942 was the high tide of Axis power: Germany dominated all of Europe, pushed further into southern Russia and Egypt, and sank ships carrying U.S. reinforcements to Britain and Russia. The Soviet Union, however, rallied its people and drew on the immense resources provided by Stalin’s single-minded industrial development of the 1930s. In a series of huge and brutal battles, notably in the sieges of Stalingrad and Leningrad, the German army was slowly destroyed and pushed back into eastern Europe. By late 1944, the Allies had effectively crushed Germany on three fronts through successive invasions of North Africa, Italy, and France. Combined with logistical support by American industry, intensive aerial bombing of German cities, and Soviet military power, the Allies turned the tide of war in Europe. The end came in 1945, when Berlin fell to the Red Army, Hitler committed suicide, and American and Russian troops shook hands at the Elbe River in the center of Germany.
Japan’s invasion of China, in pursuit of imperial rule over eastern Asia, strained relations with the United States. Gambling that it could seize the industrial resources of southeast Asia from the distracted European imperial powers and fend off the United States in a defensive war, Japan attacked American forces in Hawaii and the Philippines in late 1941. By mid-1942, just as Germany was at the peak of its power in the West, Japan too dominated its hemisphere. It controlled eastern China, southeast Asia as far west as Burma, and most of the western Pacific Ocean from New Guinea to the Aleutians. It threatened Australia, India, Hawaii and Alaska. However, alarmed by totalitarian aggression in the 1930s, the United States had been moving away from its long-standing isolationist policies and had already begun a massive rearmament program. Once it entered the war in 1941, America devoted most of its resources to defeating Germany, but its military presence in Asia was still enough to overwhelm Japan. In a series of fierce naval and air campaigns, American forces advanced on Japan, island by island. By 1944, the United States retook the Philippines, began to bomb the Japanese homeland, used submarines to blockade Japan, and prepared to launch an invasion as soon as Germany surrendered. In the summer of 1945, Berlin fell and the Soviet Union soon declared war on Japan, looking to seize Manchuria and Korea. Most of Japan’s major cities had been leveled by mass firebombing, and America’s use of atomic bombs to level Hiroshima and Nagasaki led to a level of destruction never before seen. Japan’s leaders surrendered and American began to occupy the devastated country.
By a broad estimate, well over 20 million soldiers died in what would be the greatest war in history. Just as the causes of the war followed on and developed from those of the first World War, so too did the methods. The most notable difference was the increase in mobility. Improved tanks, planes, and trucks provided new offensive power, and trench warfare was replaced by spread-out battlefields that devastated entire regions and cities. New weapons were born of modern science: radar to detect planes and ships, sonar to locate submarines, computers to break codes and calculate aim, aircraft carriers to sink battleships, and jet planes and rockets to deliver high-caliber explosives against tanks—and even cities. The most devastating weapon of all was the nuclear bomb that America used to end the war against Japan.
In addition to soldiers, 30 million civilians were killed by military action and state persecution. Wartime famine and disease laid waste to another 20 million lives. Although all the nations committed war crimes, Germany and Japan adopted the most brutal policies with explicitly racist ideologies of conquest. Millions died in both East Asia and Europe, in work camps set up to detain, torment, and murder political or racial enemies. The noncombatant death toll in Europe is estimated at 20 million, as Jews, Communists, labor leaders, prisoners of war, homosexuals, the mentally disabled, and Romani peoples were shot or gassed to death. In particular, Hitler targeted the Jews, blaming them for all of Germany’s problems. Six million of Europe’s 9.5 million Jews were killed in the Nazi Holocaust. Millions of East Asians, from China and Korea to Indonesia and the Philippines, were also killed as the Japanese advanced their conquests. Added to this misery were the uncountable wounded, traumatized, and separated. Beyond the human cost the destruction of wealth, by explosive and expenditure, was on the order of a trillion U.S. dollars at the time.
There was no armistice or peace conference at the end of World War II. The Allies demanded unconditional surrender, and the devastated Axis nations had no choice but to accept. Both Japan and Germany were occupied by Allied armies. Within the framework of the occupation, the Allies purged the ruling classes, imposed extensive social reforms, and attempted to remake the countries in the image of their own (Western or Soviet) societies. They also held war trials in which top generals and government officials were charged, convicted, and sometimes executed, for crimes against humanity. This set a new precedent in international law, as making war could now be punishable in international courts.
Even more so than after World War I, the victors were in hardly better shape than the losers. France and China, and other countries of Europe and East Asia, had been devastated by their conquerors and occupiers. Great Britain, although never invaded, was crippled economically and like France was already losing control of parts of its empire.
The clearest “victor” was the United States, which had suffered smaller losses in terms of men killed, had built up its industrial power to supply much of the Allied forces, and, except for the attack on Hawaii in 1941, had not been touched by actual combat. One lesson had been learned: the United States recognized the consequences of its isolationism between the wars and took a strong position of leadership in the postwar world. At the Bretton Woods conference in 1944, the United States committed to support the economies of other develop nations by linking its strong domestic currency and undamaged economy to the international gold standard. This enabled a rapid recovery of Europe and Japan over the following decades. In short, a nation crippled by the Depression had been unified and revitalized by the war, and its outlook on world affairs was both positive and triumphant.
On the other side of the world, the Soviet Union had faced annihilation and survived to emerge as a great military power, dominating northern Eurasia, but it was not nearly as secure and strong as the United States. Its losses had been almost 27 million, and immense areas had been occupied and ruined by the war. Building on its successful alliance with the non-Communist Anglo-Americans, it participated in the founding of the United Nations, and in the war crimes tribunals. However, it refused to join the American-led postwar international economic system, instead following both ideological and national security imperatives by establishing a rigid Communist hegemony in Eastern Europe. Like the United States, the Soviet Union took a renewed sense of national greatness from its victory, and foresaw opportunities to spread Communism across a shattered world.
The victorious Allies resolved to try again with an international organization. The United Nations (UN), headquartered in New York City, attempted to fix the flaws of the failed League of Nations. The Security Council, with permanent membership for the five Allied victors of the war (United States, U.S.S.R., Great Britain, France, and the Republic of China), was specifically tasked with keeping the peace by military action if necessary, subject to veto by any of the great powers. The General Assembly of all the member nations is a forum for discussing world problems and their solutions. It cannot pass laws, but it can raise issues and suggest resolutions. Shortly after its founding, the UN was busy settling disputes in the Middle East and helping the many refugees left by World War II. It made its strongest mark in the Korean War (1950–1953), authorizing an international armed force to resist the Communist attack. In later years, as the Cold War split the Allies into opposition and many new nations emerged with little stake in a Western-oriented world order, the UN has proved less able to maintain world peace. Just as with the failed League, without the sovereign power of military enforcement, international organizations must mirror the actual balance of national power at the global level.