WW II had two main theaters, one in Europe and one in Asia. In Europe, Hitler led the Nazis to launch a war of aggression to unify Europe, while in Asia, the Japanese imperial army led by Japanese military Imperialists launched a huge war of aggression against China and Asia. Although the two countries have built capable and ferocious armies, neither Germany nor Japan could sustain a long-term war if the invaded countries struggle hard to resist or they joined forces together to resist the enemy. Germany and Japan are small and medium-sized countries with limited domestic resources. War consumption and supplies needed will sooner or later exhaust domestic reserves. It is unreliable to depend on conquered land to manufacture and supply war needs for a long period of time. The U.S. is the world's largest economy. In the early days of WW II, as a by-standing observer and a selling military supplies trader was indeed good for the U.S. to enrich its treasury and people. When Japan realized that its plan of conquering China in six months had become a pipe dream (China put up a fight for eight years and in the end, China won) and worried that its supply for the war would not be sufficient, they were concerned that they might not count on the U.S. for the continuous supply of coal, iron, and oil, key war materials. Therefore, they took the risk of attacking the U.S., hoping to secure their military resources needs by defeating the U.S. However, Japan misjudged the strength of the U.S. and failed. Consequently, the U.S. declared war against Japan.
On the two major battlefields of WW II, the cooperation between Germany and Japan could not prevent their doomed final defeat. The Japanese military training was rigorous, and the soldiers were blindly loyal to the Japanese emperor. Although the Japanese emperor had surrendered, the Japanese troops scattered all over Asia, especially on the Pacific islands, still resisted desperately. When Germany announced its defeat in May 1945, Japan was still struggling, but the Sino-Japanese War had killed and tied up many Japanese troops in China, making Japan unable to support other battle-grounds. On August 6th, the U.S. dropped the first atomic bomb on Hiroshima, and then Russia declared war on Japan. Then on August 9, the U.S. dropped the second atomic bomb on Nagasaki, Japan. The two atomic bombs caused 129,000 to 226,000 casualties Then the Emperor of Japan announced his unconditional surrender. Although Japan's final defeat was predictable, the power of the atomic bomb was so astonishing, which gave the stubborn Japanese militants a face-saving excuse to surrender for the sake of saving the lives of the Japanese people. Today, the rightwing Japanese still harbor the thoughts that Japan was not fairly defeated in WW II. This kind of mentality challenges the theory of ‘nuclear detent' (the deterrent effect of a nuclear bomb believed by Japanese people), a hidden worry for the resurrection of the Japanese Imperial Army.
The lethality of the atomic bombs used in WW II was deeply imprinted in the minds of the Japanese people. After WW II, Japan was under American occupation. Japan was rebuilt with a new constitution that would forbid establishing any invasive military force. The Japanese public is against nuclear weapons. However, post WW II, the U.S. and the Soviet Union provoked a cold war and an arms race, including nuclear weapons. As a result, the U.S. and the Soviet Union have more than 10,000 nuclear bombs in reserves, the Soviet Union has 6,257 nuclear bombs, the U.S. has 5,550, and the remaining 1197 (13,000-6257-5550) nuclear warheads are owned by China, Britain, France, India, Israel, Pakistan, and North Korea. The power of modern nuclear bombs can be as large as 12 million tons of TNT, equivalent to 60 times the power of the atomic bomb dropped on Nagasaki. At that time, the number of casualties in Nagasaki exceeded 100,000. Based on that number, 13,000 nuclear bombs may kill more than 78,000,000,000 people (13,000 times 60 times 100,000 = 78 billion people), which is far more than the global population of 7.9 billion. This means that if a nuclear war broke out, all mankind would be destroyed.
At the end of the Cold War, the U.S. and the Soviet Union had a Strategic Arms Limitation Treaty (SALT I 1972 AND II 1979, Strategic Arms Limitation Treaty and START I 1991 and START II 1994, 2011, Strategic Arms Reduction Treaty), both sides agreed not to increase nuclear arms competition and limit interception and attacks the number of nukes. The two sides also agreed to limit the development of nuclear weapons by other non-nuclear states. However, the effect of nuclear limitation is not enforced rigorously. Not only North Korea continues to strengthen its nuclear weapons, but Iran in the Middle East is also committed to the development of nuclear weapons. After the outbreak of the Russo-Ukrainian War in February 2022, the U.S. and NATO both supported Ukraine, including greatly prolonging the war, hence forcing Russia to declare willingness to use strategic nuclear weapons and to terminate the START treaty, but agreeing to hold the 1500 nuclear missile limit. The continuation of the Russia-Ukraine war certainly increases the possibility of a nuclear war, which is why China is willing to mediate a truce between Russia and Ukraine.
Triggerring of a nuclear war is made by a country with nuclear weapon, one of the nine countries mentioned above. But the power of nuclear weapons is so devastating, who would be willing to be retaliated by another nuclear state? Therefore, from a strategic logic point of view, a small nuclear-armed country (a nation with a small number of nuclear warheads) will never attack a nuclear-armed country (a country with a large number of nuclear warheads and the ability to retaliate), nor will it easily use nuclear weapons against non-nuclear-armed countries, because other nuclear-armed countries may find an excuse to retaliate. This is the role of the nuclear weapon protection umbrella. So many countries that have enemies or confrontational neighbors may want to choose a large nuclear weapon-holding country as a protector (umbrella). Since the Cold War, although the Soviet Union and Warsaw have disintegrated, the U.S. and the NATO alliance are still there. The role of Russia as a nuclear protector has been reduced, but the U.S. is still the largest nuclear umbrella. The most obvious situation is that European countries, such as the small Nordic nations and European states newly becoming independent from the Soviet Union, have the need to rely on the protection of the U.S. Similarly, countries such as Japan, South Korea, the Philippines, and Singapore in Asia also have national security concerns and nuclear threat, hence the U.S. has naturally become their protector.
However, the world situation is constantly changing, despite the persistence of ideology confrontation. After the disintegration of the Soviet Union, Russia was mainly committed to economic development; and did not compete with the U.S. as it did during the Cold War. As the U.S. continues to push NATO to expand into Northern Europe and approach Russia, Russia really wants to join the European Union (EU) and become a member of Europe. However, under the leadership of the U.S., NATO and the EU are unwilling to allow Russia to join them, completely ignoring the possible changes of communist states. Indeed, changes can be observed, apart from the weakening of Russia's national strength and its intention to move closer to the West, China has established a Chinese-style development model and has successfully become the world's second largest economy without imitating the hegemonic capitalism of the U.S. In addition, various forms of socialism are also gradually rising in South America and Africa. These changes have greatly altered the world stage. However, the U.S. still sticks to its hegemonic capitalist thinking, and still wages proxy wars in third places with third parties. Using military power to solve international conflicts. The U.S. provocation that led to the Russo-Ukrainian war was a proxy war against fast-growing China. Beyond that, Taiwan was prepared as the next proxy battlefield. Both Russia and China have nuclear weapons, so the U.S. naturally does not want to cause nuclear wars to inflict itself, but the U.S. should worry that when the proxy war heats up out of control, nuclear weapons may be used. During the Russia-Ukraine war, Russia has stated that it does not rule out the use of nuclear weapons. In the Taiwan Strait crisis, the U.S. has no reliable guardrails to prevent Japan, North and South Korea, and even the Philippines from escalating a conflict encircling China into a deadly nuclear confrontation between the U.S. and China's nuclear ships, nuclear submarines, and nuclear missiles.
Therefore, from a strategic point of view, the start of a nuclear war is unpredictable, and any situation may go out of control, whether it is between a large and small nuclear-armed country or a non-nuclear-armed country. The most sensible policy is to resolve disputes and conflicts through diplomatic means. China’s proposal of a cease-fire for the Russo-Ukraine war is a right step in the right direction. The U.S. should get involved with a positive attitude.