The United States was the first country to develop nuclear weapons, and has since been on the forefront of technological development, extent of nuclear weapons production, as well as their means of delivery. The United States currently stands for 58 per cent of the world’s combined expenses on nuclear weapons, and has likely spent over 10 trillion dollars on such weapons up until now.
The United States conducted its first nuclear test—code-named Trinity—in July 1945 at the Alamogordo test site in New Mexico. The US atomic bombings of Hiroshima on August 6, 1945 and of Nagasaki on August 9, 1945 marked the first and—so far—the only occasions on which nuclear weapons have been used in war to destroy cities. During the seven decades of the nuclear age, the US has been in the forefront of nuclear weapons development and production, and has spent more than 10 trillion dollars on nuclear warheads, delivery systems, and nuclear weapons infrastructure.
During the Cold War, the United States produced more than 70 000 nuclear weapons and conducted 1054 atmospheric, underwater, and underground tests on sites mostly in Nevada, Alaska and the Pacific Ocean. (The US conducted its final nuclear test in 1992, although it has not yet ratified the Comprehensive Test Ban Treaty.) Since the 1980s, the United States has dismantled and destroyed a significant number of nuclear weapons as a result of disarmament treaties with the Soviet Union/Russia.
According to figures released at the 2015 NPT Review Conference, the US has dismantled 10,251 nuclear warheads over the past 20 years, another 2,500 warheads have been retired and are scheduled for elimination, and the active US nuclear arsenal consisted of 4,717 nuclear warheads as of September 2014. The current total US nuclear inventory is about 6,800 warheads, or about 44 per cent of all nuclear weapons in the world. Although the US dismantled about 1,800 nuclear weapons per year during the 1990s, the pace of reductions has slowed considerably in recent years.
The US nuclear arsenal is deployed across a so-called nuclear triad consisting of strategic bomber aircraft, land-based intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs).
The United States Air Force (USAF) operates the first leg of the triad, which consists of a nuclear-capable fleet of 18 B-2 “Spirit” and 76 B-52H “Stratofortress” strategic bombers. The bombers are organized in seven bomb squadrons, which are based in the US at the Minot, Barksdale, and Whiteman Air Force Bases. US strategic bombers are equipped with both B61 gravity bombs and air-launched cruise missiles (ALCMs).
- B-52H: The B-52H is the latest iteration in a long series of B-52 designs stemming from the early Cold War. Deployed initially in 1961, the B-52H has remained in the US strategic bomber fleet despite its age. The B-52H has a range of up to 16,000 kilometers (which can be extended through mid-flight refuelling), making it one of the longest-range bombers in the world. The nuclear-capable B-52Hs are currently equipped with AGM-86 ALCMs having a 5-150 kt yield.
- B-2A: The B-2A is a modern strategic bomber incorporating stealth features to allow it to slip past air defences. Developed in the late 1970s, the bomber has also been used for conventional missions in Kosovo, Iraq and Afghanistan. The B-2A has an 11,000-km range, which can be extended through mid-flight aerial refuelling. The nuclear-capable B-2As are equipped with B61 and B83 variable-yield gravity bombs (allowing the yield to be changed during a mission for different targeting requirements). The B61 bombs can be set to 0.3 to 340 kt yields, and the B83 up to 1,2 Mt yields.
Unlike most other nuclear weapon states, the United States does not have its own rocket or artillery forces for the land-based missiles that comprise the second leg of the triad. The US Air Force is responsible for the sole strategic nuclear ballistic missile in the US arsenal, the Minuteman III. The 450 ICBMs (as of late 2013) are based in silos in Wyoming, North Dakota and Montana.
- LGM-30G Minuteman III: The Minuteman III is a three-stage, solid-fuelled intercontinental-range ballistic missile with a 13,000 km
range. The missiles are currently (2015) undergoing a multi-billion dollar modernization programme, which will extend the lifetime of the missiles until 2030. The missiles currently carry single 300-335kt W87/W78 warheads, which have been “de-MIRVed” (multiple warheads have been removed and replaced with a single warhead) in order to comply with reductions negotiated with Russia under New START. The US nevertheless retains the option of “re-MIRVing” the warheads for future strategic purposes.
The third leg of the US nuclear triad—assigned to the United States Navy—consists of 14 Ohio-class nuclear ballistic missile submarines (SSBNs) capable of firing submarine-launched ballistic missiles (SLBMs). The US currently keeps these SSBNs on active patrol, with eight submarines deployed in the Pacific and six in the Atlantic Ocean. Each SSBNs is currently equipped with 24 launch tubes (the number will be reduced to 20 in 2015) designed to fire the UGM-133A Trident II SLBM from either a submerged or surface position.
- UGM-133A Trident II: The US currently deploys a single type of SLBM for its sea-based nuclear force. The Trident II is a three-stage, solid-fuelled SLBM equipped with 4 MIRVed W76/W88 warheads with 100-455 kt yields, having a range of more than 7,400 km.
Nuclear weapons modernization
In 2007, the US restarted small-scale production of replacement warheads for older nuclear weapons. The Bush administration proposed large-scale production under the Reliable Replacement Warheads (RRW) programme, but the US Senate did not approve the funds. The Obama administration has since committed itself to produce no new nuclear warheads, though this pledge is ambiguous at best, since the US is currently conducting a large and costly modernization of the entire US nuclear arsenal.
For instance, all land-based Minuteman III missiles, according to a US ICBM Program Analyst, will be “basically new missiles except for the shell”. Similarly, US SSBNs are currently being modernized in order to carry newer and more accurate SLBMs. So far, 500 out of a total of 1,200 nuclear warheads on the Trident II-SLBMs have been replaced with the new W76-1 warhead. The warhead replacements will improve US targeting capabilities, and the process of replacement is scheduled to last until 2020. The USAF is also planning to replace the B-2 Spirit and B-52H Stratofortress strategic bombers, and to modernize the tactical B-61 gravity bombs and nuclear air-launched cruise missiles. This project alone has been estimated to cost more than $10 billion. The new US F-35 fighter-bomber is also being designed to carry tactical nuclear weapons deployed in Europe.
The United States is the most transparent nuclear weapon state with regard to its stockpiles of both nuclear warheads and inventories and production of highly-enriched uranium (HEU) and plutonium. In 1996, the US released a plutonium production declaration covering the years 1944 to 1994, followed by a declaration of HEU production in 2006, covering the years 1944 to 1996. The US updated these figures in 2006 (HEU) and 2012 (plutonium). These transparency declarations were offered as a confidence-building measure.
The US drew sharp criticism in 2012 after three anti-nuclear activists exposed critically flawed security routines at the Y-12 HEU storage site in Oak Ridge, Tennessee, which contains about 400 metric tonnes of HEU. The activists, including an 82-year-old nun, were able to break the security fences and were reported to have spent more than two hours at the site before being detected, raising concerns about the security measures at fissile material storage facilities.
The role of nuclear weapons in national security strategy
The most important public documents on US nuclear weapons policy are the Nuclear Posture Review (NPR, most recently updated in April 2010), National Security Strategy (September 2002) and National Strategy to Counter Weapons of Mass Destruction (December 2002). NPRs released by the Bush administration in 2001 and 2002 indicated that the US was prepared to use nuclear weapons against non-nuclear armed opponents, as well as in pre-emptive strikes. In March 2005, the US Department of Defense (DoD) published a draft revision of US nuclear weapon doctrine. The draft was unusually clear in stating that nuclear weapons could be used in situations other than retaliation for a nuclear attack against the US (16). The draft drew sharp criticism, and was subsequently withdrawn.
These policy documents make it quite clear that nuclear weapons retain an important role in US security strategy, and establish that nuclear weapons could be used in ways that are not limited strictly to deterrence of a nuclear attack by others. Some analysts have raised concerns that these policies could have been used to support nuclear strikes against countries such as Iran and North Korea. The Obama administration, however, in its most recent NPR (2010), has appeared to scale back the more prominent role given to nuclear weapons under former president Bush. The US now states that it will not use or threaten to use nuclear weapons against non-nuclear-armed NPT Member States that fully comply with their treaty obligations. The US, however, reserves its right to use nuclear weapons in what it considers extreme situations against countries that already have nuclear weapons, as well as countries that are outside the NPT.
President Obama’s vision of a nuclear-weapon-free world
Before he was elected US president in 2008, Barack Obama had presented a 14-point plan to reduce the global threat of nuclear weapons. In a speech he gave in Prague in April 2009, President Obama repeated his vision of a world free of nuclear weapons, while adding that this goal might not be realized in his lifetime. Obama pledged, however, to take concrete steps to reduce the number of nuclear weapons in the world, and to reduce their role in US defence strategies.
In the autumn of 2009, Obama personally led a meeting in the UN Security Council where the majority of the nuclear-weapon powers were present. The meeting was about non-proliferation of nuclear weapons, but also covered reductions of existing nuclear weapon stockpiles. The US and Russia agreed to extend the START treaty until a new disarmament treaty could be negotiated. This New START treaty was signed by presidents Medvedev and Obama in April 2010. According to the New START, which has been ratified by both countries, the US and Russia are to reduce their number of deployed nuclear warheads by an additional one third, down to maximum of 1,550 nuclear warheads each. While Russia has fully implemented the treaty according to published reports, the US is on a schedule to complete its New START obligations by 2018.
Some concerns have been raised about current disarmament efforts between Russia and the US, as warhead dismantlement has stalled around the 1,550 mark. Russia, which met the 1,550 target in 2013, reportedly exceeded that number slightly in 2014 when it introduced new SS-27 ICBMs. US warhead numbers have fluctuated as well, rising slightly above the 1,550 mark due to the counting rules for warheads deployed on its SSBN fleet.
In the spring of 2010, the US arranged the first of several international summits on measures to prevent the spread of nuclear materials to terrorist groups and other states. The US and Russia subsequently pledged to reduce their inventories of separated plutonium.
In 2009, President Obama received the Nobel Peace Prize, to both his own and the international community’s surprise. The Nobel committee justified the decision partly on Obama’s vision of reducing the global threat of nuclear weapons. Despite this, Obama has met fierce domestic opposition in the US Congress, and has not conducted more than meagre reductions in the US nuclear weapon arsenal. Compared to his predecessor, George W. Bush, who slashed in half the number of US nuclear weapons, US disarmament under president Obama remains rather meagre.
Last update: March 15, 2017