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United States

Overview

Last Updated: June, 2019

The United States possesses a substantial nuclear weapons arsenal and associated delivery systems and is one of the five nuclear weapon states recognized by the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). The United States is a party to the Biological and Toxin Weapons Convention (BTWC) as well as the Chemical Weapons Convention (CWC), and does not have offensive biological and chemical programs.

Nuclear

The United States used nuclear weapons on Hiroshima and Nagasaki in August 1945, making it the only country to ever use nuclear weapons during a conflict. At its 1967 peak, the U.S. arsenal contained 31,255 nuclear warheads. [1] As of the latest U.S. government disclosures (September 2017), the arsenal consisted of 3,822 nuclear warheads, with thousands more retired and awaiting dismantlement. [2] In April 2019, The United States Department of Defense declined to publish nuclear stockpile numbers, reversing a policy of nuclear stockpile transparency begun in 2010 under the Obama administration. [3]

The United States possesses a land-sea-air “nuclear triad” of delivery systems, comprising intercontinental ballistic missiles (ICBMs), ballistic missile submarines (SSBNs), and strategic bombers. The United States also deploys approximately 150-200 nuclear gravity bombs in five NATO countries: Belgium, Germany, Italy, the Netherlands, and Turkey, as part of its commitment to extended deterrence. [4]

In addition to the NPT, the United States is a party to several treaties related to the reduction and control of nuclear weapons. The U.S.-Russian New START Treaty, which entered into force on 7 February 2011, reduced both countries’ strategic nuclear arsenals to 1,550 deployed strategic warheads and 700 deployed strategic delivery vehicles. [5] The United States is also a member of export control organizations aimed at limiting the proliferation of sensitive nuclear technologies, including the Nuclear Suppliers Group (NSG) and the Zangger Committee (ZAC).

After conducting a total of 1,054 nuclear tests since 1945, the United States has maintained a unilateral moratorium on nuclear tests since 1992. [6] The United States signed the Comprehensive Nuclear Test Ban Treaty (CTBT) in 1996 but has not ratified the treaty, and is unlikely to pursue ratification under the Trump Administration. [7] The United States opposes the Treaty on the Prohibition of Nuclear Weapons (TPNW), led a multi-nation boycott of the treaty’s negotiation in 2017, and does not intend to sign, ratify, or become party to it. [8]

The United States is currently modernizing all three legs of its nuclear triad, which, according to independent analysts’ estimates, could cost over one trillion dollars over a 30-year period. [9] Additionally, the Trump administration’s 2018 Nuclear Posture Review called for the development of new types of nuclear weapons, including a new low-yield nuclear warhead which began production in 2019. [10] Under President Trump, the United States has shown ambivalence and occasional hostility toward arms control diplomacy. The Trump administration formally began the withdrawal process from the U.S.-Russia Intermediate-Range Nuclear Forces Treaty (INF), and has declined to take a position on renewing the New START Treaty when it expires in 2021. [11]

Biological

Beginning in 1943, the United States weaponized a variety of pathogens and toxins for use against humans and plants, including Bacillus anthracis (anthrax), Francisella tularensis (tularemia), Venezuelan equine encephalitis virus (VEE), Clostridium botulinum (Botulinum Toxin), and staphylococcus aureus (staphylococcal enterotoxin B or SEB). [12] President Nixon renounced biological weapons on 25 November 1969, and the U.S. signed the Biological and Toxins Weapons Convention (BTWC) on 10 April 1972. [13] Between May 1971 and February 1973, the United States destroyed its entire BW stockpile. [14]

The United States has sought to cement norms against the proliferation of biological weapons through multilateral efforts such as the Proliferation Security Initiative (PSI) and export control regimes such as the Australia Group (AG). In September 2018, the Trump administration released the 2018 National Biodefense Strategy, which seeks to manage the risk of naturally occurring, accidental, or deliberate biological threats. [15]

Chemical

During WWI, the United States manufactured, stockpiled, and used chemical weapons (CW), primarily mustard agent and phosgene gas, but has not used CW since. [16] In 1969, President Nixon signed an executive order halting further production of unitary chemical weapons, and the United States ratified the Geneva Protocol in 1975. [17] On 1 June 1990, Presidents Bush and Gorbachev signed the Bilateral Destruction Agreement (BDA), halting all production of new U.S. and Soviet CW. [18]

The United States ratified the Chemical Weapons Convention (CWC) in 1997, obligating the country to destroy all of its CW stockpiles by 2007. [19] The United States has received multiple extensions, and is currently on track to complete destruction of chemical stockpiles by September 2023. [20] The United States promotes CW nonproliferation through the Australia Group (AG), an export control mechanism.

Missile

The United States produces and deploys highly sophisticated liquid- and solid-fueled ballistic missiles and cruise missiles. According to a 2018 estimate, the United States deploys 400 LGM-30G Minuteman III nuclear-tipped intercontinental ballistic missiles (ICBM) at bases in Montana, North Dakota, and Wyoming. The Navy deploys 280 UGM-133A Trident II D-5 submarine launched ballistic missiles (SLBM) on 14 Ohio-class nuclear-powered ballistic missile submarines (SSBN). The Air Force deploys 20 B-2A bombers that can carry up to 16 nuclear bombs and 46 B-52H Stratofortress bombers that can each carry up to 20 AGM-86B nuclear tipped air-launched cruise missiles (ALCM) each. [21]

Following the signing of the Intermediate-Range Nuclear Forces Treaty (INF) in 1987, the United States eliminated its entire stockpile of intermediate-range ballistic missiles (IRBM) and medium-range ballistic missiles (MRBM). [22] The Trump administration formally began the withdrawal process from the INF Treaty on 2 February 2019, although it has not declared plans to deploy IRBM and MRBM missiles. [23]

The United States has historically devoted considerable resources to missile defense. The most recent Missile Defense Review, released in January 2019, proposed new space-based interceptors and an expanded scope for the U.S. missile defense mission. [24]

The United States participates in missile technology nonproliferation through its membership in the Missile Technology Control Regime (MTCR) and the Hague Code of Conduct Against Ballistic Missile Proliferation (HCOC), which is designed to supplement and bolster the MTCR.

Sources:
[1] Hans M. Kristensen and Robert Norris, "Global Nuclear Weapons Inventories, 1945-2009," Bulletin of the Atomic Scientists 65, No. 4, 2009, www.thebulletin.org.
[2] DoD Open Government, "Stockpile Numbers," U.S. Department of Defense, September 30, 2017, www.open.defense.gov.
[3] Stephen Aftergood, “Pentagon Blocks Declassification of 2018 Nuclear Stockpile,” Federation of American Scientists, 17 April 2019, www.fas.org; Hans Kristensen, “Pentagon Slams Door on Nuclear Weapons Stockpile Transparency,” Federation of American Scientists, 17 April 2019, www.fas.org.
[4] Robert S. Norris and Hans M. Kristensen, “United States Nuclear Forces, 2018,” Bulletin of the Atomic Scientists 74, No. 2 (March 2018), p. 120-131.
[5] Office of the Press Secretary, "Key Facts about the New START Treaty," 26 March 2010, www.whitehouse.gov; Peter Baker, "Senate Passes Arms Control Treaty with Russia, 71-26," New York Times, 22 December 2010, www.nytimes.com; "New START Enters into Force," Global Security Newswire, 7 February 2011, www.globalsecuritynewswire.org.
[6] U.S. Department of Energy Nevada Operations Office, "United States Nuclear Tests: July 1945 through September 1992," DOE/NV—209-REV 15, December 2000, www.nv.doe.gov; U.S. Congress, "Energy and Water Development Appropriations Act, 1993," 102nd Congress H.R. 5373, 2 October 1992, http://thomas.loc.gov.
[7] "Country Profiles: United States of America," Comprehensive Test Ban Treaty Organization, www.ctbto.org.
[8] United States Mission to the United Nations, “Joint Press Statement from the Permanent Representatives to the United Nations of the United States, United Kingdom, and France Following Adoption of a Treaty Banning Nuclear Weapons," 7 July 2017, usun.state.gov.
[9] Jon B. Wolfsthal, Jeffrey Lewis, Mac Quint, “The Trillion Dollar Nuclear Triad,” James Martin Center for Nonproliferation Studies, January 2013, www.nonproliferation.org; Kingston Reif, “U.S. Nuclear Modernization Programs,” Arms Control Association, Updated August 2018, www.armscontrol.org.
[10] “Nuclear Posture Review,” United States Department of Defense, February 2018, media.defense.gov; Ankit Panda, “U.S. Begins Production of Low-Yield Submarine-Launched Ballistic Missile Warhead,” The Diplomat, 30 January 2019, www.thediplomat.com.
[11] Julian Borger, “Donald Trump Confirms U.S. Withdrawal from INF Nuclear Treaty,” The Guardian, 1 February 2019, www.theguardian.com; Aaron Mehta, “One Nuclear Treaty is Dead. Is New START Next?”, Defense News, 23 October 2018, www.defensenews.com.
[12] Eric Croddy, Chemical and Biological Warfare: A Comprehensive Survey for the Concerned Citizen (New York: Springer-Verlag, 2002), p. 31.
[13] Jeanne Guillemin, Biological Weapons (New York: Columbia University Press, 2005), p. 125, 127. The United States ratified the BTWC on 10 April 1975.
[14] Joseph Cirincione, Jon B. Wolfsthal, and Miriam Rajkumar, Deadly Arsenals: Nuclear, Biological, and Chemical Threats, Second ed. (Washington, DC: Carnegie Endowment for International Peace, 2005), pp. 60, 212. This stockpile included over 40,000 liters of anti-personnel biological warfare agents and 5,000 kilograms of anti-agricultural agents.
[15] “National Biodefense Strategy,” The White House, 18 September 2018, whitehouse.gov.
[16] Jonathon B. Tucker, War of Nerves: Chemical Warfare from World War I to Al-Qaeda (New York: Anchor Books, 2007), p. 19.
[17] Joseph Cirincione, Jon B. Wolfsthal, and Miriam Rajkumar, Deadly Arsenals: Nuclear, Biological, and Chemical Threats, Second ed. (Washington, DC: Carnegie Endowment for International Peace, 2005), p. 213.
[18] Jonathon B. Tucker, War of Nerves: Chemical Warfare from World War I to Al-Qaeda (New York: Anchor Books, 2007), pp. 245-295.
[19] "Status of Participation in the Chemical Weapons Convention as at 21 May 2009," OPCW Technical Secretariat, S/768/2009, 27 May 2009, www.opcw.org.
[20] OPCW Executive Council, “Draft Report of the OPCW On the Implementation of the Convention on the Prohibition of the Development, Production, Stockpiling, and Use of Chemical Weapons and on Their Destruction in 2017,” 10-12 July 2018, www.opcw.org.
[21] Robert S. Norris and Hans M. Kristensen, “United States Nuclear Forces, 2018,” Bulletin of the Atomic Scientists 74, No. 2 (March 2018), p. 120-131.
[22] Joseph Cirincione, Jon B. Wolfsthal, and Miriam Rajkumar, Deadly Arsenals: Nuclear, Biological, and Chemical Threats, Second ed. (Washington, DC: Carnegie Endowment for International Peace, 2005), pp. 85-87.
[23] Julian Borger, “Donald Trump Confirms U.S. Withdrawal from INF Nuclear Treaty,” The Guardian, 1 February 2019, www.theguardian.com.
[24] “Missile Defense Review,” United States Department of Defense, 17 January 2019, media.defense.gov; Thomas Karako, “The 2019 Missile Defense Review: A Good Start,” Center for Strategic and International Studies, 17 January 2019, www.csis.org.

Get the Facts on United States
  • Deploys approximately 200 nuclear weapons in five NATO countries
  • Dismantled over 13,000 nuclear warheads since 1988
  • Still in the process of destroying its chemical weapons stockpile

This material is produced independently for NTI by the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, or agents. Copyright 2019.