The United States introduced nuclear weapons to the Asian continent in 1945, via the devastating bombings of Hiroshima and Nagasaki, Japan at the end of World War II. Since that time, more Asian nations have gone on to adopt nuclear weapons technology than those of any other continent. At present, six countries in Asia have or are suspected of having nuclear weapons (counting Russia), while two more are believed to be working hard on developing nukes.
Nuclear Bombings of Japanese Cities
By 1945, the United States had succeeding in developing the world's first nuclear weapons thanks to the concerted efforts of the Manhattan Project team. With World War II dragging on in the Pacific theater, and Japan refusing to surrender, President Truman authorized the August 6, 1945 bombing of Hiroshima. Almost 70% of the city was utterly destroyed by the "Little Boy" bomb, and between 90,000 and 140,000 people died within the year from the radiation blast.
While the government of Japan debated whether to surrender, the U.S. grew impatient. On August 9, a bomber flew to the city of Kokura, but cloudy weather prevented the crew from dropping the bomb. Instead, they went on to the secondary target, the port city of Nagasaki. An additional 60-80,000 people died there from the explosion of the "Fat Man" weapon.
This second calamitous attack convinced the Japanese government to surrender immediately and unconditionally. Japan had to give up its demands for retention of Korea and Formosa (Taiwan), and allow the U.S. occupation of the Japanese home islands.
Thus far, the bombings of Hiroshima and Nagasaki have been the only instances of atomic weapons being used in warfare. It is likely that tens or even hundreds of thousands of U.S. troops would have died in a ground invasion of Japan, along with countless Japanese troops and civilians. However, controversy remains due to the U.S. choice to bomb cities full of civilians, without issuing any advance warning.
Russia and China Get "The Bomb"
Before the United States even used its first atomic weapon, its erstwhile ally, the Soviet Union, discovered that the U.S. was developing this technology. The USSR launched its own weapons program, aided greatly by espionage efforts against the U.S. program. On August 29, 1949, the Soviet Union tested its first atomic bomb.
With the U.S. and the USSR left standing as the world's two superpowers in the post-war era, an ideological show-down developed between capitalism and communism. Known as the Cold War, this era was dominated by the arms race, which prominently featured nuclear weapons and the threat of global annihilation.
Meanwhile, relations between the two large communist powers - Russia and China - deteriorated in the late 1950s and early 1960s. Although the problems were based in part on ideological differences, the USSR's refusal to share nuclear technology with China was another major issue of contention. Mao Zedong ordered research into nuclear weapons in 1953; the program was disguised as a civilian power-generation scheme.
The USSR was initially supportive of China's efforts, but by 1959 it withdrew technical aid. Nevertheless, China tested its first atomic bomb on October 16, 1964, becoming the fifth nation with The Bomb. (In Europe, Great Britain and France had also successfully developed nuclear weapons by this point.)
End of the Cold War
Although the Cold War ended with the collapse of the Soviet Union in 1990-1991, the threat from nuclear weapons in Asia persisted. In fact, during the chaotic early post-Soviet era, the world learned that newly independent Kazakhstan possessed some 1,800 nuclear warheads that had been left there by the former Soviet rulers. Concern mounted that the Kazakh government might sell its nuclear arsenal to Iran or to a terrorist organization.
In the end, Kazakhstan agreed to return all of the "stranded" nukes to Russia. Within four years, the entire arsenal was on Russian soil.
The Second Nuclear Age
As the 20th century progressed, other regional powers began to conduct research and development of nuclear weapons as well. In Asia, the recurring confrontation between India and Pakistan prompted those two countries to seek nuclear capabilities.
Following the 1971 Indo-Pakistani War, a short but sharp conflict that ended with Bangladesh's secession from Pakistan, Indian Prime Minister Indira Gandhi authorized the production and testing of a nuclear weapon. India's first nuclear test took place on May 18, 1974 at Pokhran. The device was given the ironic name "Smiling Buddha."
In reaction to these developments, in 1972 Pakistani Prime Minister Zulifkar Ali Bhutto (father of Benazir Bhutto) initiated Pakistan's own nuclear program, called "Project 706." Pakistan tested its first miniature nuclear weapon in 1983, and its first full-scale nuclear weapons on May 28 & 30, 1998. The full-scale tests were a response to India's "Operation Shakti," a May 11 & 13 series of tests carried out despite the protests of the United States.
Although a number of nations condemned India for Shakti, and the U.S. imposed economic sanctions, Israel issued a statement of support. In the statement, Israel noted that India's reasons for developing nuclear weapons were "the same as Israel's." This was one of several faux-accidental admissions from Israel that it has a secret nuclear arsenal.
Officially, Israel will neither confirm nor deny that it is a nuclear power. However, a retired Israeli nuclear engineer revealed in 1986 that the Israelis were in fact the sixth nation to develop nukes, after China. Israel's current arsenal size is unknown, with estimates ranging between 75-80 warheads on the low end, to upwards of 400 on the high end. From time to time, Israeli officials "let slip" a comment about their nuclear weapons - likely as a warning to hostile neighboring states.
Syria and Iran: Working on Proliferation
Two of the nations that present likely targets for any Israeli nuclear attack are Syria and Iran. As a result, both may have secret weapons programs of their own. However, neither has conducted any known weapons testing.
Although Iran and Syria both declare that their uranium enrichment activities and purchases of nuclear technology are for peaceful electricity-generation only, they are cagey about releasing details on how much enriched uranium they produce and other key data. In addition, Iran has admitted to having at least two underground nuclear facilities, concealed in mountainsides to minimize the risk of preemptive attack by Israel.
The threat of an Israeli strike is not theoretical. In 2007, Israel attacked and destroyed a Syrian nuclear site that it alleged was being built for weapons research. The Syrians responded that the new reactor was for peaceful purposes. However, Syria had just taken delivery of a shipment of nuclear technology from North Korea.
The Final Member of the Nuclear Club
On October 9, 2006, Japanese and U.S. seismologists detected a magnitude 4 earthquake in North Korea. Kim Jong-il's government then announced to the world that it had successfully conducted its first nuclear weapons test.
At first glance, North Korea seems like an odd candidate for nuclear proliferation. The only other nuclear power in the area, China, is its closest ally. Japan has sworn off nuclear weapons since its 1945 experience, and South Korea has no nukes of its own (although the substantial U.S. military presence there implies American support up to and including the use of "borrowed" nuclear warheads).
Not only does North Korea face the implicit threat of American nukes; it also stands at a severe economic and demographic disadvantage compared with its rival, South Korea. North Korea likely views nuclear weapons technology as essential to maintain equal footing in negotiations with the South, and to extract food aid during the frequent famines. After all, a first strike against Seoul could wipe out 1/4 of South Korea's population, including most of the government.
Conclusion: Is Proliferation in Asia a Serious Threat?
The history of nuclear weapons in Asia over the last century shows that those countries that face perceived threats from their neighbors are eager to acquire nukes as a deterrent. Nuclear programs spring up wherever hostile fault lines exist: between China and the USSR in the 1960s, between India and Pakistan in the 1990s, across the Korean DMZ in the 21st century, and between Israel and its neighbors for decades. Of nine nuclear-armed states in the world, six are in Asia, as are the two states in hottest pursuit of the technology.
Perhaps we can take some comfort, however, from the fact that none of these nations have actually used their nuclear weapons in anger. The specter of Japan's experience with first-generation atomic weapons in 1945 may still haunt Asia with sufficient dread to stave off full-scale nuclear war.