Military forces provide states with means of leverage beyond the various nonmilitary means of influence widely used in international bargaining.
Political leaders face difficult choices in configuring military forces and paying for them. Military spending tends to stimulate economic growth in the short term but reduce growth over the long term.
In the 1990s, military forces and expenditures of the great powers—especially Russia—were reduced and restructured.
Military forces include a wide variety of capabilities suited to different purposes. Conventional warfare requires different kinds of forces than those needed to threaten the use of nuclear, chemical, or biological weapons.
Except in time of civil war, state leaders—whether civilian or military—control military forces through a single hierarchical chain of command.
Military forces can threaten the domestic power of state leaders, who are vulnerable to being overthrown by coups d’état.
Control of territory is fundamental to state sovereignty and is accomplished primarily with ground forces.
Air war, using precision-guided bombs against battlefield targets, proved extremely effective in the U.S. campaigns in Iraq in 1991, Serbia in 1999, Afghanistan in 2001, and Iraq in 2003.
Small missiles and electronic warfare are increasingly important, especially for naval and air forces. The role of satellites is expanding in communications, navigation, and reconnaissance.
Weapons of mass destruction—nuclear, chemical, and biological—have been used only a handful of times in war.
The production of nuclear weapons is technically within the means of many states and some nonstate actors, but the necessary fissionable material (uranium-235 or plutonium) is very difficult to obtain.
Most industrialized states, and many poor ones, have refrained voluntarily from acquiring nuclear weapons. These states include two great powers, Germany and Japan.
More states are acquiring ballistic missiles capable of striking other states from hundreds of miles away (or farther, depending on the missile’s range). But no state has ever attacked another with weapons of mass destruction mounted on ballistic missiles.
Chemical weapons are cheaper to build than nuclear weapons, they have similar threat value, and their production is harder to detect. More middle powers have chemical weapons than nuclear ones. A new treaty bans the possession and use of chemical weapons.
Several states conduct research into biological warfare, but by treaty the possession of such weapons is banned.
Slowing the proliferation of ballistic missiles and weapons of mass destruction in the third world is a central concern of the great powers.
The United States is testing systems to defend against ballistic missile attack, although none has yet proven feasible, and withdrew from the ABM treaty with Russia to pursue this program.
The United States and Russia have arsenals of thousands of nuclear weapons; China, Britain, and France have hundreds. Israel, India, and Pakistan each have scores. Weapons deployments are guided by nuclear strategy based on the concept of deterrence.
Arms control agreements formally define the contours of an arms race or mutual disarmament process. Arms control helped build confidence between the superpowers during the Cold War.
