"The United States has historically led the international community in establishing regimes intended to limit the spread of nuclear, chemical, and biological weapons and missiles. The regimes and their member countries use cooperative and coercive measures to achieve nonproliferation and counterproliferation objectives. Multilateral agreements and organizations are supplemented by strong bilateral cooperation among key allies, unilateral political and economic actions, and recourse to military operations should they become necessary. Congress supports the nonproliferation regimes primarily by providing statutory authority and funding for U.S. participation, establishing policy, and mandating punitive actions to help enforce the international standards set by the regimes. The term 'regime' often refers to the entire array of international agreements, multilateral organizations, national laws, regulations, and policies to prevent the spread of dangerous weapons and technologies. The nuclear nonproliferation regime is presently the most extensive, followed by those dealing with chemical and biological weapons, and then by the missile regime. The difficulty of producing nuclear weapons material (highly enriched uranium or plutonium) and the great awareness of nuclear weapons' destructiveness together have been conducive to creating a complex regime with widespread agreement on the priority of nuclear nonproliferation. Chemical weapons are easier to make and rely on readily available precursors, and they are far less destructive. Biological weapons also rely on dual-use technology, and as technology has spread, efforts to build a more extensive control regime have intensified. Finally, there is no international consensus on the danger of missile proliferation to support a nonproliferation treaty or a binding regime with enforcement mechanisms."
CRS Report for Congress, RL31559