Nuclear Weapons

Today nuclear weapons are built in many sizes and shapes not available in the 1940s and 1950s, and are designed for use against many different types of military and civilian targets. Some weapons are less powerful than 1,000 tons of TNT, while others have the explosive force of millions of tons of TNT. Small nuclear shells can be fired from cannons. Nuclear warheads mounted on missiles can be launched from land-based silos, ships, submarines, trains, and large wheeled vehicles. Several warheads can be fitted into one missile and directed to different targets in the same geographic area upon reentry into Earth's atmosphere. These multiple independently-targeted reentry vehicles (MIRVs) can release ten or so individual nuclear warheads far above their targets, making enemy interception more difficult and increasing the deadliness of each individual missile.

In general, nuclear weapons with "low" yields (in the kiloton, rather than the megaton, range) are termed "tactical," and are designed to be used in battle situations against specific military targets, such as a concentration of enemy troops or tanks, a naval vessel, or the like. These weapons are termed tactical because the word tactics, in military jargon, refers to the relatively small-scale maneuvers undertaken to win particular battles. Larger nuclear weapons are classed as "strategic," because the word strategy, again in military jargon, refers to the large-scale maneuvers undertaken to win whole wars. Strategic nuclear weapons are targeted mostly at cities and at other nuclear weapons, and are mostly designed to be dropped by bombers or launched on ballistic missiles; tactical nuclear weapons are delivered by smaller devices over shorter distances. However, one nation's "tactical" warhead may be another's "strategic" warhead: Russia, for example, maintains that U.S. tactical warheads in Western Europe are in fact strategic warheads, since they can strike targets inside Russia itself, while Russian "tactical" warheads in the same arena cannot strike the U.S. heartland.

In the summer of 2002, President George W. Bush's administration sought and received permission from Congress to design a new class of nuclear weapons: "mini-nukes," relatively low-yield tactical nuclear weapons for use against underground bunkers and other small battlefield targets. Advocates of these new weapons point to the uniquely powerful, compact "punch" that can be delivered by a nuclear weapon; critics argue that even a small nuclear weapon may cause many civilian casualties, and, more important, that actual use of a nuclear weapon of any size would break the taboo on such use that has held since the end of World War II, making the use of larger, more destructive nuclear weapons more likely in future conflicts.

Even the ability of nuclear weapons to release radioactivity has been exploited to create different types of weapons. "Clean bombs" are weapons designed to produce as little radioactive fallout as possible. A hydrogen bomb without a uranium jacket would produce relatively little radioactive contamination, for example. A "dirty bomb" could just as easily be built, using materials that contribute to radioactive fallout. Such weapons could also be detonated near Earth's surface to increase the amount of material that could contribute to radioactive fallout. "Neutron" bombs originally designed to be used against Soviet forces in areas of Europe with cultural treasures (art museums, etc.) are able to shower battle fields with deadly neutrons that can penetrate buildings and armored vehicles without destroying them. Any people exposed to the neutrons, however, would die. (Neutron bombs also destroy with blast effects, but their deadly radiation zone extends far beyond their blast area)

The United States and Russia signed a Strategic Arms Reduction Treaty in 1993 to eliminate two thirds of their nuclear warheads in ten years. By 1995, nearly 2,500 nuclear warheads had been removed from bombers and missiles in the two countries, according to U.S. government officials. ("Elimination," in this context, does not necessarily mean dismantlement; many of the weapons that have been "eliminated" by treaty have been put in storage.) Although thousands of nuclear weapons still remain in the hands of many different governments, especially those of the U.S. and the Russian Federation, recent diplomatic trends have at least helped to lower the number of nuclear weapons in the world. This has caused many people to erroneously assume that the danger of nuclear weapons evaporated with the end of the Cold War.

However, the number of nations possessing nuclear weapons continues to increase, and the possibility of nuclear weapons being used against human beings for the first time since World War II may be larger than ever. In May 1995, more than 170 members of the United Nations agreed to permanently extend the Nuclear Non-Proliferation Treaty, first signed in 1960. Under terms of the treaty, the five major countries with nuclear weapons—the United States, Britain, France, Russia, and China—agreed to commit themselves to eliminating their arsenals as an "ultimate" goal. The other 165 signatory nations agree not to acquire nuclear weapons. Israel, which many Western intelligence assert possesses some nuclear weapons (but officially denies doing so), did not sign the treaty. Two other nuclear powers, India and Pakistan, also refused to renounce nuclear weapons. India and Pakistan, each of which probably possess several dozen nuclear weapons, have fought a number of border wars in recent decades, and in 2002 came frighteningly close, as many observers thought, to fighting a nuclear war. As of this writing (February 2003), North Korea has reactivated its nuclear-weapons-material production facilities and is engaged in a tense diplomatic standoff with the United States, which insists that North Korea abandon its nuclear-weapons program.