Nonproliferation is the prevention of the spread of nuclear weapons to countries that currently do not have them, often called “horizontal proliferation.” (Proliferation can also refer to the qualitative improvement of existing nuclear weapon stockpiles, or “vertical proliferation,” and this is discussed in the arms limitation treaty section.) In the 21st Century, non-state actors such as terrorist organizations have become a new focus of nuclear non-proliferation, especially because they are widely considered to be undeterrable. With regional tensions fueling nuclear arms races and ambitions, terrorist groups seeking nuclear weapons, and the increasing availability of technology needed to produce nuclear materials, concerns nuclear proliferation are ironically more pronounced today than even during the darkest days of the Cold War.
Early Nuclear Developments
The need to prevent the spread of nuclear weapons was evident from the first days of the nuclear era. On November 15, 1945, the United States, the United Kingdom, and Canada proposed the establishment of a United Nations Atomic Energy Commission for the purpose of "entirely eliminating the use of atomic energy for destructive purposes." The Baruch plan of 1946, offered by the United States, sought to forestall nuclear arms proliferation by placing all nuclear resources under international ownership and control.
Early postwar efforts to achieve agreement on nuclear disarmament failed and assumptions about the scarcity of nuclear materials and the difficulty of mastering nuclear technology were inaccurate Four more states exploded nuclear devices - the Soviet Union in 1949, the United Kingdom in 1952, France in 1960, and the Peoples Republic of China (China) in 1964.
In the early 1960s, the search for peaceful applications of nuclear energy brought advances in the technology of nuclear reactors for the generation of electric power. By 1966 nuclear power reactors were operating, or under construction, in five countries and it was thought that those numbers would only expand. Nuclear reactors produce not only power, but also plutonium—a fissionable material that can be chemically separated and used in the manufacture of nuclear weapons. The equipment used to enrich uranium for nuclear fuel could also continue enriching the uranium to bomb-grade concentrations.
The diversion of nuclear materials from their peaceful uses to military purposes thus became a great concern, as did the possibility that a growing number of nations would become nuclear weapons powers. Without an international nuclear nonproliferation regime, the risk of a nuclear war starting through the escalation of regional conflicts or even as a result of accidental or unauthorized use, seemed likely to increase.
A succession of initiatives beginning in the 1950s by both nuclear and non-nuclear powers sought to check nuclear proliferation. On December 9, 1953, U.S. President Eisenhower made his “Atoms for Peace” speech to the UN General Assembly (UNGA), proposing that a new international agency be created to share nuclear materials and information for peaceful purposes. Contributions of uranium and fissile materials from nuclear states would be transferred for peaceful uses of atomic energy in non-nuclear states. A treaty establishing this agency would result in increasing the peaceful uses of atomic energy, reducing the stockpile of fissile material available for weapons, and helping prevent non-nuclear weapon states from developing these weapons as they began independent nuclear energy programs.
Negotiations on such an agreement began in 1954, resulting in the 1956 Statute of the International Atomic Energy Agency (IAEA). This treaty authorized the creation of the IAEA and gave it the responsibility of providing information and assistance to countries seeking to use nuclear energy for peaceful purposes, performing inspections of nuclear facilities to ensure material was not diverted to weapons production, and providing early warning if material was being diverted.
On August 29, 1957 Canada, France, the United Kingdom, and the United States submitted a package of nuclear nonproliferation proposals to the Five-Power Subcommittee of the United Nations Disarmament Commission. Created January 11, 1952, The UN Disarmament Commission consisted of the 11 members of the United Nations Security Council (UNSC) plus Canada. The mandate of the Five-Power Subcommittee was "to seek, in private, solutions to the problems discussed within the Commission." This was the latest in a series of nonproliferation proposals the Subcommittee considered throughout the 1950’s, which included the idea that “each party undertakes not to transfer out of its control any nuclear weapons, or to transfer to it of weapons,” except in self-defense. Although the Soviet Union also wanted to prevent states from acquiring nuclear weapons, it claimed this Western formula would enable a potential aggressor to judge its own actions and use nuclear weapons in “any armed conflict which any Government may regard as an attack on itself.” The Soviets instead sought to couple a ban on the transfer of nuclear weapons to other states with a prohibition on stationing nuclear weapons in foreign countries. The Disarmament Commission could not agree on an international nonproliferation treaty.
The need for an international nonproliferation treaty gained renewed urgency in February 1960 when France tested its first nuclear weapon in Algeria. In 1961 the UNGA adopted a resolution sponsored by Ireland (the Irish Resolution), “Prevention of the Wider Dissemination of Nuclear Weapons.” This resolution called on all states, particularly the nuclear powers, to conclude an international agreement to refrain from relinquishing control of nuclear weapons and from transmitting information necessary for their manufacture to states not possessing such weapons. The Irish Resolution also called for a nonproliferation agreement that would contain provisions under which non-nuclear weapon states would undertake not to manufacture or otherwise acquire control of such weapons.
In 1962, Secretary of State Dean Rusk showed Soviet Foreign Minister Andrei Gromyko a basic nonproliferation agreement draft based on the Irish Resolution. Gromyko rejected the proposal, possibly due to fears that it did not limit potential NATO nuclear sharing, or a multilateral force (MLF). Minister Gromyko focused on a broader Soviet proposal at the following UN Disarmament Committee meeting that included complete nuclear disarmament, not limited to the Irish Resolution’s nonproliferation. The disagreement between the NATO countries’ interest in a MLF and the Soviet response stalled negotiations on an international nuclear nonproliferation treaty for several more years.
Despite strong disagreement on the issue of collective defense arrangements, both the U.S. and Soviet Union recognized the desirability of an agreement on nuclear nonproliferation. Moreover, the interest of non-nuclear weapon states in a nuclear nonproliferation treaty was increasing, as evidenced the 1964 African summit conference and the Cairo conference of nonaligned states. Eventually, in informal negotiations with the Soviet Union, the U.S. agreed to a nuclear nonproliferation treaty with a provision prohibiting the five nuclear weapon states (NWS) from transferring control over any of their nuclear weapons to any non-nuclear weapon state (NNWS). This provision also called on the NWS not to help or encourage other states in the manufacture, acquisition, or control of nuclear weapons. Lastly, the nations that did not have nuclear weapons had to agree upon joining the treaty to not receive, manufacture, or otherwise acquire nuclear weapons and not to seek or receive any assistance in their manufacture. In 1965 the UNGA adopted resolution 2028, listing five main principles that should underpin a nuclear nonproliferation treaty:
1. All states, NWS and NNWS, should be obligated not to engage in nuclear weapon proliferation
2. There should be a balance between NWS and NNWS obligations
3. The treaty should be a step toward nuclear disarmament, as well as toward general and complete disarmament
4. There should be practical provisions to ensure the treaty’s effectiveness
5. The treaty should not curtail the right of any group of states to establish nuclear-weapon-free zones (NWFZs).
In the mid-1960s the Eighteen Nation Disarmament Committee (ENDC) was the multilateral negotiating forum for international disarmament agreements. Meeting on UN premises in Geneva, the ENDC was the predecessor to the Conference of the Committee on Disarmament (1968-1978) and now the Conference on Disarmament (1979-Present). In 1965, the U.S. and USSR submitted drafts of a nonproliferation treaty to the ENDC and UNGA. In May 1966, the U.S. Senate unanimously passed a resolution sponsored by Senator Pastore of Rhode Island and 55 other Senators commending the efforts to reach a nuclear nonproliferation agreement and supporting continued efforts.
Early discussions on the text of a nuclear nonproliferation treaty in the ENDC met with slow progress and eventually the United States and Soviet Union met for bilateral talks in the fall of 1966. These talks focused on how to word the sections dealing with transfers of nuclear weapons from NWS and the non-acquisition of such weapons by NNWS. The United States wanted the treaty to permit the existing US-UK collaborative arrangements to continue as well as allow existing NATO arrangements for the transfer of nuclear weapons for use on NNWS-owned delivery systems in the event of war. The Soviet Union, however, wanted the treaty to prevent any MLF arrangement from becoming legitimate. In early 1967 the two sides agreed on language, based on U.S. nuclear energy legislation, that would become articles I and II of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). The agreed upon language allowed the existing NATO nuclear arrangements to continue, but prevented multilateral nuclear weapon sharing such as MLF.
The U.S. then began consultations with allies who raised a number of questions regarding the effect of any nuclear nonproliferation treaty on NATO defense arrangements. The United States explained that any future treaty would govern the proliferation of nuclear weapons/explosive devices, but not their delivery systems. Thus, NATO consultation and planning on nuclear defense would not be prohibited, nor would the deployment of U.S.-owned and controlled nuclear weapons be banned on the territory of non-nuclear NATO member states. This perspective on NATO nuclear sharing under a future nuclear nonproliferation treaty was shared with the Soviet Union, which did not challenge American interpretations.The remainder of the 1967 and 1968 NPT discussions focused on three main issues that concerned NNWS:
Verification/Safeguards: There was general agreement that the Treaty should include provisions designed to detect and deter the diversion of nuclear materials from peaceful to military purposes. However, the USSR insistence that all NNWS accept IAEA safeguards had to be reconciled with the desire of the non-nuclear members of the European Atomic Energy Community (EURATOM) (Belgium, the Federal Republic of Germany, Italy, Luxembourg, and the Netherlands) to preserve their regional system of monitoring and control of their nuclear energy activities. The Soviets considered this a form of self-policing rather than independent monitoring and wanted full IAEA safeguards to apply to all states in the region. To meet these concerns, the final draft of the NPT provided that NNWS parties could negotiate safeguards agreements with the IAEA either individually or together with other states (Article III, Section 4).
Balanced Obligations: NNWS parties held that their renunciation of nuclear weapons should be accompanied by a commitment on the part of the NWS to reduce their nuclear arsenals and to make progress on measures toward comprehensive disarmament. India and Mexico particularly, among NNWS, sought negotiations toward a comprehensive nuclear test ban treaty (CTBT). As a result, the eventual NPT text called for the achievement of a CTBT in the preamble and included Article VI, affirming the intentions of the parties to the NPT to negotiate in good faith to achieve the cessation of the nuclear arms race, nuclear disarmament, and general and complete disarmament (GCD). This bargain was necessary to secure the agreement of NNWS to sign the NPT and commit to permanently renouncing nuclear weapons.
Security Assurances: Non-nuclear weapon states parties, particularly non-aligned members of the ENDC, sought guarantees that renunciation of nuclear arms would not place them at a permanent military disadvantage. Since both superpowers were providing alliance partners with extended nuclear deterrence security guarantees, non-aligned countries wanted the NPT to provide them with similar guarantees. The non-aligned states were specifically seeking both negative assurances that NWS would not attack them with nuclear weapons, and positive assurances that NWS would come to their aid if they were attacked with such weapons.
To address this issue, the United States, Soviet Union, and United Kingdom submitted a proposal to the ENDC on March 7, 1968, which called for security assurances to take the form of a U.N. Security Council Resolution, supported by declarations from the three powers. The resolution, noting the concerns of states wishing to subscribe to the NPT, would recognize that nuclear aggression or the threat of nuclear aggression against a NNWS would create a situation requiring immediate action by the Security Council.
Signing and Ratification
After passage by the ENDC, the UNGA approved Resolution 2372 on June 12, 1968, which endorsed the latest version of the Nuclear Nonproliferation Treaty. This resolution requested the United States, the United Kingdom, and the Soviet Union to open the treaty for signature. These states were charged with accepting instruments or documents of ratification for accession to a treaty and notifying all other states parties of any new ratifications. On June 15, the UNSC passed the security assurance resolution, Resolution 255, recognizing nuclear aggression or the threat of nuclear aggression against NNWS as a situation requiring immediate action by the Security Council. Among the NWS, France abstained from voting on the resolution, its representative saying that while not meaning to be an obstacle to adoption of the proposal, France did not believe the nations would receive adequate security guarantees without nuclear disarmament.
Subsequently, the NPT was opened for signature on July 1, 1968. Sixty-two states, including the three depository states, signed the treaty that day. France and China did not initially sign the NPT, but France pledged to behave as if it were a member.
On July 9, 1968 President Johnson transmitted the NPT to the Senate for its advice and consent, but prospects for early U.S. ratification dimmed after the Soviet invasion of Czechoslovakia that August, and the Senate adjourned without voting on the Treaty. In February 1969, President Nixon requested Senate approval of the NPT and that March the Senate gave its advice and consent to ratification. The Nuclear Nonproliferation Treaty entered into force with the U.S. deposit of ratification on March 5, 1970, as the required 40 states had already ratified it.
By the end of 1975, 97 nations had become parties to the NPT. The number of states parties increased to 114 by the end of 1980, 133 by the end of 1985, and 141 by the end of 1990. As of 2009, all U.N.-recognized states were parties to the NPT except India, Pakistan, and Israel.
The NPT recognized five NWS – these were states that had exploded a nuclear device prior to 1968, the year the negotiations for the Treaty ended. South Africa acceded to the NPT as a NNWS in 1991 after dismantling its small number of nuclear warheads. China and France acceded to the Treaty as NWS on March 9 and August 3, 1992, respectively. Additionally, the Russian Federation joined the NPT as the successor nuclear weapon state to the USSR on December 24, 1991. Other former Soviet states that had nuclear weapons on their new national territories joined the NPT as NNWS in 1993 (Belarus) and 1994 (Kazakhstan and Ukraine).
Also in 1994, Brazil committed itself to the Treaty of Tlatelolco, which created the Latin America and Caribbean Nuclear Weapons Free Zone (NWFZ). Although not officially acceding to the NPT as a NNWS until 1998, the Treaty of Tlatelolco was a legal commitment by Brazil to not acquire nuclear weapons. Argentina acceded to the NPT as a NNWS in 1995, Cuba acceded to the Treaty as a NNWS in 2002, followed by Timor-Leste in 2003 and Montenegro in 2006.
Nuclear Nonproliferation Treaty Provisions
In broad outline, the basic provisions of the NPT are designed to:
• Prevent the spread of nuclear weapons (Articles I and II).
• Provide assurance, through international safeguards, that the peaceful nuclear activities of non-nuclear weapon states parties (those that had not already developed nuclear weapons by January 1, 1967) will not be diverted to making such weapons (Article III).
• Promote, to the maximum extent consistent with the purposes of the Treaty, the peaceful uses of nuclear energy, with special attention given to development needs. This includes the potential benefits of any peaceful application of nuclear explosion technology being made available to non-nuclear parties under appropriate international observation (Articles IV and V).
• Express the determination of the parties that the Treaty should lead to further progress in comprehensive arms control and nuclear disarmament measures (Article VI).
 Truman, H., Attlee, C., & King, W. (1945, November 15). Declaration on Atomic Bomb By President Truman and Prime Ministers Attlee and King. NuclearFiles.org: Project of the Nuclear Age Peace Foundation. Retrieved June 23, 2010, from http://www.nuclearfiles.org/menu/key-issues/nuclear-energy/history/dec-truma-atlee-king_1945-11-15.htm
 Digital Documents and Photographs Project. (2007, September). The Eisenhower Presidential Library and Museum Homepage. Retrieved June 23, 2010, from http://www.eisenhower.archives.gov/research/digital_documents/Atoms_For_Peace/Atoms_For_Peace.html
 Legault, A., Fortmann, M., & Ellington, D. (1992). Pg. 89. In A diplomacy of hope: Canada and disarmament, 1945-1988. McGill-Queen’s University Press 1992. Retrieved from http://books.google.com/books?id=CkaV0twc93IC&source=gbs_navlinks_s
 Ibid, Pg. 89 - 91.
 United Nations, Disarmament Commission. (1957, August 29). Canada, France, United Kingdom of Great Britain and Northern Ireland and United States of America: working paper: proposals for partial measures of disarmament (1957, August 29, DC/SC.1/66, pg. 74). In Supplement from January to December 1957. New York. Retrieved June 23, 2010, from http://disarmament.un.org/Library.nsf/0bb8a163b66d627f85256beb0073f596/60420ec6791b105e8525765b004c0f1d/$FILE/Supplement%20for%201957.pdf
 Ibid. Pg. 75-76.
 Ibid. Pg. 103.
 United Nations, General Assembly. (1961, December 4). Prevention of the Wider Dissemination of Nuclear Weapons (1665 (XVI)). Retrieved from http://daccess-dds-ny.un.org/doc/RESOLUTION/GEN/NR0/167/18/IMG/NR016718.pdf
 A MLF was supported by some in the U.S. government whereby ships owned by several NATO countries, including the United States, would be armed with U.S. nuclear weapons and manned by officers and sailors from the U.S. and other participating countries.
 United Nations, General Assembly. (1965, November 19). Non-Proliferation of Nuclear Weapons (2028(XX)). Retrieved from http://daccess-dds-ny.un.org/doc/RESOLUTION/GEN/NR0/217/91/IMG/NR021791.pdf
 U.S.Cong. (1946, August 1). Atomic Energy Act of 1946 (Vol. I) [Cong. Doc. from 79th Cong., 2nd sess.]. Washington, DC. Retrieved from http://www.osti.gov/atomicenergyact.pdf
 U.S.Cong. (1998, August 30). Atomic Energy Act of 1954 [Cong. Doc.]. Washington, DC. Retrieved from http://epw.senate.gov/atomic54.pdf
 European Atomic Energy Community is an international organization established in 1957 by the original European Economic Community partners for cooperation in nuclear energy matters.
 General and complete disarmament refers to the liquidation of all nuclear weapons and their delivery vehicles.
 States party to the Non Aligned Movement are not part of international security alliances with the nuclear powers, such as NATO and the Warsaw Pact.
 United Nations, Security Council. (1968, June 19). UNSC Resolution 255. Retrieved from http://daccess-dds-ny.un.org/doc/RESOLUTION/GEN/NR0/248/36/IMG/NR024836.pdf
 United Nations, Office for Disarmament Affairs. 2000 NPT Review Conference. Retrieved from http://www.un.org/disarmament/WMD/Nuclear/2000-NPT/2000NPT.shtml
 The DPRK withdrew from the NPT in January 2003. However, many states question the legality of North Korea's withdrawal because it claimed to be renewing an earlier notice of withdrawal and because the UNSC could not agree to a response of the DPRK’s notification of “extraordinary events” and “supreme interests.”
 United Nations, Office for Disarmament Affairs. Multilateral Arms Regulation and Disarmament Agreements. Retrieved from http://disarmament.un.org/treatystatus.nsf
 The U.S., Russia, Belarus, Ukraine, and Kazakhstan signed the Lisbon Protocol on May 23, 1992, which stated that all five states would become parties to START and Belarus, Ukraine, and Kazakhstan promised to accede to the NPT as NNWS “in the shortest time possible.”