I'm sure all my readers are familiar with the basic story of how nuclear weapons came to be upon the earth -- although I fear that most young people today are not. (They think that WWII was fought between the U.S. and its valiant German allies against the Soviet Union.) Prominent physicists, led by the most famous of them all, Albert Einstein, feared that Nazi Germany would develop an atomic bomb, and so they urged Franklin Roosevelt to get there first. The program to develop the bomb was carried out in total secrecy. If truth is the first casualty of war, democracy is the second. (That's why Dick Cheney is so fond of it, for both reasons.) It turned out that Germany was never close to developing nuclear weapons, and Germany surrendered before the U.S. tested its first atomic bomb. The American people were just as surprised as the Japanese when the United States Army Air Force obliterated the Japanese city of Hiroshima on August 6, 1945, using a single nuclear weapon, nicknamed Little Boy. The pilot who commanded the mission named the airplane after his mother, Enola Gay Tibbets. His actions killed about 180,000 people, half immediately, the remainder over the next few months. Since then, thousands more have died from the latent effects of radiation. Nearly all of the casualties were civilians. The United States went on to destroy a second Japanese city, Nagasaki, three days later.
The motivation for the attack, and its morality, have been debated ever since. The U.S. had demanded that Japan surrender on July 26, but had not mentioned the atomic bomb. Many people feel that a demonstration, for example by exploding a bomb over the ocean near Japan, would have been just as effective in bringing about Japan's surrender as actually vaporizing a civilian population. A common interpretation is that the real motive was to impress the Soviet Union, as Japan's defeat was already assured in any case. I am not a historian, and in any case I know that nobody had the power to read Harry Truman's mind during his lifetime, so I don't know definitely why he gave the orders that he gave.
In any event, the Soviet Union definitely was impressed. Although U.S. leaders believed that their monopoly over nuclear weapons would lead to a pax Americana, the Soviets had started their own nuclear weapons program in 1943, and exploded a weapon in August 1949. The nuclear arms race was on. With the collapse of the Soviet Union in 1991, the U.S. and Russia pulled back from the brink, and their arsenals have contracted somewhat from the peak.
Nevertheless there are currently approximately nearly 26,000 nuclear explosive devices on the planet. Russia possesses more than half of these, some 15,000, but most of its weapons are not currently operational. Russia and the U.S. have approximately equal numbers of operational weapons, 5,800 and 5,700 respectively. France has 350, China and the UK 200 each. Israel is believed to have about 80 but Israel blatantly lies to the world and pretends it doesn't have any. Pakistan has about 60, India about 50, and North Korea an unknown number in the single digits (which may or may not work).
One third of the United States' weapons are W76 hydrogen bombs, with an explosive yield of 100 kilotons -- about 7 to 10 times the power of the weapons that destroyed Hiroshima and Nagasaki. (The exact yield of these weapons is disputed. It's usually said to be 15 kilotons but may have been less.) The U.S. possesses other weapons with yields as high as 475 kilotons, and so-called "tactical" weapons with yields as low as 1 kiloton, which can be fired from artillery. Russian bombs tend to be bigger, because their missiles are less accurate.
The only purpose of the large bombs -- the majority in every nation's arsenal -- is to destroy cities and cause mass casualties, on the order of millions of people killed immediately and millions more horribly burned and maimed, many of whom will die sooner or later of radiation poisoning or cancer. The "tactical" weapons are intended to be used against targets such as military bases or troop formations, but they could just as well be used against population concentrations or industrial facilities.
As for delivery, the U.S., Russia and China can attack every place on the planet using land-based or submarine-based missiles, or long-range bombers. France and the UK can do the same using their nuclear submarine fleets.
The remaining nuclear powers are regional threats. India and Pakistan's arsenals are principally aimed at each other, although the possibility of some sort of conflict developing with China may have been on the minds of Indian leaders when they decided to develop their weapons. The rationale behind the Israeli arsenal is unclear. No regional nuclear power is capable of attacking Israel. It must be acknowledged, however, that nuclear weapons do not have to be delivered by missiles or aircraft. They could be placed on a ship and sailed into a harbor, or smuggled into a country and sent anywhere in an ordinary automobile.
The U.S. and Russia have pledged to reduce their "deployed" weapons to 2,200 each by 2012, although the effect of that is unclear, since non-deployed (so-called "stockpiled") weapons might be deployable within a short time. (This is the basis on which Israel maintains the fiction that it does not possess nuclear weapons - they have to tighten a bolt before the weapons become operational.)
The current White House occupant said recently that Iran cannot be permitted to have the knowledge necessary to make nuclear weapons. In that case, it is much too late. Here is a detailed, functional design for a nuclear weapon, specifically Fat Man, the weapon that destroyed Nagasaki, so you know it works. Now they'll have to kill you. Actually, Hiroshima style bombs are much easier to make, but they require weapons grade uranium, which is difficult to obtain. Fat man was a plutonium bomb. Plutonium is easy to get, it can be chemically separated from used reactor fuel, but it requires a more complex and precise bomb design.
Now, I personally do not know whether the Iranian leadership actually intends to make a nuclear weapon. The fact is, they have perfectly legitimate reasons for wanting to develop nuclear power. Iran has a lot of petroleum, but its production is declining even as its internal need for energy is growing. Nevertheless, if they do want to have nuclear weapons, it's pretty difficult to explain why they should not. It's perfectly okay for Israel, Pakistan, India, China, etc. to have nuclear weapons. What's different about Iran? We could, I suppose, get into an argument about what countries are and are not state sponsors of terrorism, or have unstable or irrational leadership, or are "rogue states," or whatever labels you like to throw around, but here's the bottom line.
Under the Nuclear Non-Proliferation Treaty, to which all but four nations are signatories (Iran is a signatory; Israel is not), the nuclear powers are committed to ultimate disarmament. Based on that promise, the other states have pledged not to acquire nuclear weapons. But the United States has absolutey no intention of disarming. Indeed, the administration is proposing to replace its arsenal of W76 warheads with a new generation of similar weapons, and has also proposed developing entirely new kinds of nuclear weapons. The nuclear weapons which the U.S. proposes to retain in perpetuity are more than sufficient to destroy all of civilization and quite possibly exterminate humanity.
Iran has offered to participate in the creation of a nuclear free zone in the Middle East. I don't know if they were serious, but the U.S. rejected the proposal out of hand, for the obvious reason that it would require Israel to disarm, and it would also require the United States to remove the nuclear weapons it currently maintains on ships in the vicinity of the Arabian/Persian Gulf -- and may, for all we know, have deployed at its airbases in Iraq. (It would not surprise me, how about you?)
Here's what I think. Nuclear weapons are an abomination which must not be permitted to exist. The other threats facing humanity are trivial compared to this one. We might find global climate change and resource depletion and infectious disease outbreaks will be awfully unpleasant, but we can survive them all with our civilization and cultural heritage largely intact. And, whatever harm comes from them, we did it by stupidity and short-sightedness and greed. We made nuclear weapons on purpose, for no other reason than to dominate people who don't have them and destroy them at our whim. That is stupid, and short-sighted, and greedy, but it is also evil.