The Manhattan Project, one of the greatest scientific undertakings in human history, cost thousands of man-hours, the brightest minds, and billions of dollars, created the first nuclear weapons system in history. After years of theory, deduction and testing, the atomic bomb was successfully studied and dropped into the Japanese Empire, thus ending World War II, and the explosion of the atomic bomb changed the world forever.
But if the Manhattan Project fails and the Allies don't invent nuclear weapons, what will happen to history?
Operation Fall (1945-1946)
Ever since the United States decided in 1945 to use Little Boys and Fat Boys, there has been debate about the ethics of abandoning the use of nuclear weapons for civilians. While the moral questions behind such a major choice can be endlessly debated, the results speak for themselves. Atomic bombs could bring war to an end quickly. But without the atomic bomb, the war could have dragged on for at least another year, or even longer.
The Allied attack on the Japanese mainland was known as Operation Fall and consisted of operations, Olympics and Little Crowns. It was an ambitious plan of attack, which would be the largest naval extermination operation in history, with the aim of forcing Japan to surrender through the occupation of conventional ground forces.
The Olympic Plan of Action began shortly after the capture of Okinawa, which provided the Allies with a powerful forward base from which to coordinate their offensive. The goal of the Olympic operation was to occupy the western island of Kyushu. If successful, the allies would be in a good position to make a final attack on Tokyo and the Emperor's Group.
The main problem in attacking Japan was that, due to the mountainous and rocky terrain, there were few places for the Allies to land safely on the islands. The Mongols had paid a terrible price hundreds of years ago, and allied war planners knew that a forced landing would not be easy.
Casualties continued to surge during the planning phase, causing front-line generals to be acutely anxious about the success rate of such an attack. Estimated casualties soared from 150,000 to nearly 1 million, but there was no other way but the Japanese adamantly refused to surrender. Despite his uneasiness, Operation Doom was launched on November 1, 1945.
The military operation to land in Kyushu did not go well, and despite overwhelming air superiority and naval support, the beach landings met with fierce Resistance from the Japanese. Suicide squads fought furiously, and the beach was flooded with mines and laid with barbed wire. Allied casualties began to increase rapidly, and the pace of battle began to slow down.
After the initial lag, the Allies began to march into the interior of the island, where their experience was more terrifying than that of a small island in the Pacific. Each village was a potential threat, and the locals came up to provide rice and water, only to stab the Allied soldiers with sharpened bamboo knives as they reached for food. The forest was littered with well-equipped Japanese regular troops and militia squads, who constantly harassed advancing troops. The Allies, despite their clear military superiority, were slow to move forward.
Japan's plan was to slow down the Allies and inflict as many casualties as possible in an attempt to reach a favorable peace deal. They knew their empire was back in the dark, but if they could inflict enough casualties, they might be able to retain some of their interests in the Pacific.
Soviet intervention
After the Overwhelming Elimination of Nazi Germany by the Red Army, the Soviet Union took advantage of the Land Wars in Asia to expand its territory. They have long set their sights on the spoils of War on Manchuria and the northern Japanese islands. The Soviet Union remained temporarily allied with the United States as a pretext for joining the War in Asia. However, they did not help the Americans in their will to force Japan to surrender, but wanted to occupy as much territory as possible.
Red Army forces entered and occupied large areas of northeastern China, angering the Chinese in the civil war. At the same time, Soviet troops also began to enter the island of Hokkaido.
The Soviet Union and Japan would begin meeting secretly in 1946 with a view to reaching a separate peace agreement in which the Soviet Union received concessions from Japan on the condition that the Soviet Union withdrew from the war, allowing Japan to concentrate on defending its core. This will put immeasurable pressure on the U.S.-Soviet Union, which will begin to manifest itself in the politics of Western Europe.
Despite strong warnings from Britain and the United States, the Soviets reached an agreement with Japan, which ceded to the Soviets parts of Hokkaido, Japanese territory in Manchuria, and other outlying islands. The Soviet Union withdrew from the war with Japan to begin consolidating its power in Europe and Asia.
As the number of Allied casualties in Japan increased and Soviet ambitions were fully demonstrated, Allied commanders knew they needed to win quickly in order to re-establish a stable international order.
Japan Surrender (1947)
The fall took longer than expected, but finally won in the spring of 1947. After a year and a half of brutal and bloody fighting, the Japanese islands have become a smoking ruin. The Allied casualties exceeded 500,000 and nearly 250,000 died, but Tokyo was firmly in the hands of the U.S. military. The hard fighting of the US military in Japan has left the US military in a weak state at present, and its military strength has been greatly reduced.
In order to avoid becoming a prisoner, the emperor committed suicide with the entire imperial family. As a result of the deep contradictions between the two sides during the bloody war, the United States imposed an even more unfriendly rule in Japan. After Japan was forced to surrender unconditionally, hunger and disease were rampant, and the United States now has no will to help Japan with post-war reconstruction.
Instead, the Allies withdrew their funds, manpower, and resources from Japan and moved them back to Western Europe. The next showdown there is already in the works. To monitor the new territories the Soviets had acquired in China and northern Japan, the United States left behind an occupation army and established anti-Soviet military bases along the coast.
Instead of being reborn from the ashes and rebuilding into the world's leading economic power and democracy, Japan has become a squabbling backwater nation that will do everything in its power to repair the damage caused by World War II.
Without nuclear weapons, there would be no cold war
Because of the inherent deterrent power of nuclear weapons, the Cold War was largely indeed cold. Without nuclear deterrence, the world would remain predominantly dominated by conventional weapons and conventional military doctrines, and the world situation would be far less stable than it is now.
Despite being once an ally against the Nazis, it is clear that the West and the Soviet Union will not get along well with each other in the future. While the Allies were fighting in Japan, the Soviet Union was ruthlessly consolidating its power in Eastern Europe. The Red Army suppressed riots, purged dissidents, and those who had worked for the Nazis were brutally punished, while the Allies were busy in the Far East.
By around 1947, the Allies had seen terrible sights when they returned to Europe. The Soviet Union had established its own army, armored division, air force, and land defense system along its border with Western Europe, and no one in Washington, Paris, or London could react effectively to the military forces set by the Soviet Union.
In real history, at the end of World War II, the Soviet Union had nearly 12 million active troops, and after Japan surrendered, they were quickly demobilized to 3 million. In this timeline, they are likely to maintain a greater active military presence.
Even during the Cold War, the West was uneasy about the Red Army's numerical and military superiority in Europe. Without the deterrent of nuclear weapons, the balance of power in Europe would have been clearly in favor of the Soviet Union.
Traditional military doctrine largely follows the view that a state with military superiority and the possibility and means of potential military conflict will eventually attack their enemy. This thinking led to the outbreak of all major wars from the 19th century to the end of World War II. But nuclear weapons have changed that perception forever.
Without nuclear weapons, the Soviet Union, which planned to seize more territory in Western Europe, the Middle East, and Asia, would eventually expand its superiority. It's hard to say with certainty what will happen, but it's easy to see that what awaits people is not a Cold War, but a fierce hot war, with millions of people fighting another conventional war across vast lands.
World War III is likely to break out between the socialist camp and the capitalist camp. The death toll can be catastrophic, and it is impossible to know whether humanity will survive apocalyptic conflicts such as World War III.