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The United States’ Nuclear Posture Review––generally issued by each successive Presidential administration––describes the conditions under which U.S. nuclear weapons might be used, and describes U.S. nuclear policy, posture, and force structure, and their interaction with emerging technologies like artificial intelligence (AI). The most recent iteration–– published in 2022––states that “[i]n all cases, the United States will maintain a human ‘in the loop’ for all actions critical to informing and executing decisions by the President to initiate and terminate nuclear weapon employment.” 1 The Commander of U.S. Strategic Command testified to Congress in March 2025 that “AI will remain subordinate to the authority and accountability vested in humans,” although he did note that the service will use artificial intelligence and machine learning capabilities “to enable and accelerate human decision-making.” 2
The ultimate decision to use nuclear weapons, however, is one of the only areas relating to nuclear weapons where AI does not presently––or soon will––play an active role. The Department of Energy’s “Artificial Intelligence Strategy,” published in October 2025, and the National Nuclear Security Administration’s “Artificial Intelligence for Nuclear Deterrence Strategy,” published in 2023, both provide details as to how AI is being integrated into the nuclear mission. Of particular note is that AI is increasingly being used to support the stockpile stewardship mission by enhancing the United States’ modeling and simulation capabilities, by accelerating and automating the manufacture of systems needed for nuclear deterrence, and by assisting with the maintenance of nuclear weapon systems as they age. [3, 4]
The U.S. does not disclose the various ways in which AI is being integrated into parts of its early warning and nuclear command, control, and communications (NC3) infrastructure, although public statements from officials involved in the NC3 modernization process indicate that such integrations are indeed occurring. [2, 5]
As a party to New START––a US-Russian treaty limiting numbers of deployed strategic warheads and launchers––until March 2023 the United States disclosed its total inventory of nuclear-capable strategic launchers, including intercontinental ballistic missile launchers, submarine-launched ballistic missile launchers, and heavy bombers, on a bi-annual basis. 1 These figures were published in aggregated format on the U.S. Department of State's website, and the disaggregated data was available upon request from the U.S. Department of State. In addition, as New START focused on counting warheads and launchers, these figures did not include the total numbers of US delivery systems.
When procuring new nuclear-capable delivery systems, the United States typically discloses how many units of that system it intends to purchase. For example, the Milestone B procurement decision for the United States' new Sentinel ICBM, acquired through a Freedom of Information Act Request, noted that the United States' acquisition plan accounted for purchasing 659 units of the Sentinel. 2 It is not common practice, however, for the United States to disclose the number of missiles remaining in its inventory as these units eventually get depleted through regular flight tests and maintenance.
In addition, U.S. Air Force web-based fact sheets and its Notice of Intent to Prepare an Environmental Impact Statement for its incoming B-21 Raider heavy bomber indicates that the U.S. will purchase a “minimum of 100 aircraft.” [3, 4] In addition, officials occasionally state the number of delivery vehicles of particular types that are present in the U.S. arsenal. For example, at a conference in March 2025, the Commander of U.S. Strategic Command advocated for the Air Force to purchase 145 B-21 bombers instead of 100, which “gives us 220 bombers when the [B-52s] are included.” 5
Although primarily intended to describe plans for warhead modernization, infrastructure recapitalization, and workforce development, the U.S. National Nuclear Security Administration's annual Stockpile Stewardship and Management Plan includes a table of all current warheads and their associated delivery systems in the U.S. stockpile. For each warhead type, the table lists each delivery system that can carry that particular warhead, lists the mission (distinguishing between strategic and nonstrategic weapons), and lists which service (Air Force, Navy, or select NATO forces) is responsible for their deployment.
In the Fiscal Year 2025 Stockpile Stewardship and Management Plan, the United States includes the following categories of nuclear-capable delivery systems: Minuteman III intercontinental ballistic missile; Trident II D5 submarine-launched ballistic missile; F-15; F-16; certified NATO aircraft; B-2 bomber; F-35; and B-52 bomber. 1
The Department of Defense’s Deputy Assistant Secretary of Defense for Nuclear Matters published a revision to its Nuclear Matters Handbook––a comprehensive overview of the U.S. nuclear deterrent––in 2020. The latest edition includes a detailed examination of the National Nuclear Security Administration’s Nuclear Security Enterprise, which spans eight sites: Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Sandia National Laboratories, Kansas City National Security Campus, the Pantex Plant, the Savannah River Site, the Y-12 National Security Complex, and the Nevada National Security Site. 1
The Nuclear Matters Handbook also includes details about the “strategic materials” that are managed at each site, and their relation to the nuclear deterrent: the Los Alamos National Laboratory is currently responsible for managing plutonium pits––the core of a nuclear weapon that initiates the chain reaction required for a nuclear explosion––the Y-12 complex is responsible for managing uranium and lithium, and the Savannah River Site is responsible for managing tritium. It also notes future plans to convert the Mixed Oxide Fuel Fabrication Facility at the Savannah River Site to a plutonium processing facility that will be capable of producing at least 50 pits per year, and the recapitalization of a plutonium facility at Los Alamos National Laboratory to produce at least 30 pits per year. The handbook additionally notes that the U.S. government currently has no capacity to enrich uranium domestically, but that plans are being developed to re-establish this capability. 1
The United States discloses its total holdings of different fissile materials at different degrees of transparency, depending on the type of material.
In 1998, the International Atomic Energy Agency (IAEA) published Guidelines for the Management of Plutonium (INFCIRC/549), for which the five nuclear weapon states agreed to publish annual statements of their holdings of civil plutonium. While INFCIRC/549 covers most categories of plutonium, certain categories––such as plutonium with an isotopic concentration of plutonium-238 exceeding 80 percent, plutonium on which IAEA safeguards have been exempted or terminated, or plutonium used in gram quantities or as a sensing component in instruments––are exempt. 1 The United States’ most recent declaration, from 2023, noted holdings of less than 0.05 metric tons of unirradiated separated plutonium produced during the course of manufacture or fabrication, 4.6 metric tons of plutonium contained in unirradiated MOX fuel, and 44.6 metric tons of unirradiated separated plutonium held elsewhere––all of which were roughly the same as the previous year’s figures.
INFCIRC/549 does not cover holdings of low-enriched or highly-enriched uranium (HEU), and the United States does not regularly provide any public information on these stocks. The most recent instance of the United States disclosing details about its HEU stocks was in 2016, and included data from between 1996 and 2013. The disclosure noted that as of September 30, 2013, the United States’ total HEU inventory was 585.6 metric tons, 499.4 metric tons of which was for “national security or non-national security programs including naval propulsion, nuclear energy, and science.” The disclosure also noted that “of the remaining 86.2 metric tons, 41.6 metric tons was available for potential down-blend to low enriched uranium or, if not possible, disposal as low-level waste, and 44.6 metric tons was in spent reactor fuel.” 3
The United States is highly transparent about its modernization plans for each element of its nuclear arsenal, including warheads, delivery systems, nuclear warheads production, nuclear command and control, and the facilities, networks, and workforce that underpin them.
This degree of transparency can primarily be attributed to the fact that while presidential administrations can issue decisions and guidance about alterations to U.S. nuclear forces, those alterations must be authorized and funds must be appropriated by Congress in order to execute them. As a result, presidential administrations must justify their proposals to Congress through detailed budgetary submissions, congressional testimonies, studies, and laws that require certain types of disclosures.
By combining all of these various sources, it is not difficult to obtain a comprehensive picture of nearly every aspect of the U.S. nuclear modernization program, with the exception of certain details or studies that remain classified (e.g. the Analysis of Alternatives report for the modernization of the intercontinental ballistic missile force, which would provide critical insight into the Department of Defense’s initial justifications for the program).
For example, the Department of Defense’s 2020 publication of the Nuclear Matters Handbook provides details on each warhead, delivery system, scientific and technical facility, and elements of nuclear command, control, and communications infrastructure that are currently being upgraded or modernized. 1 In addition, the Department of Energy’s annual Stockpile Stewardship and Management Plan provides comprehensive details on each element of the nuclear security enterprise, including budgetary information and upgrades to individual warheads and facilities. 2 Detailed annual budgetary information is disclosed through presidential and service budget requests, which Congress then interrogates, authorizes, and appropriates. [3, 4, 5] Despite a degree of classification for some aspects of nuclear modernization and justification, many documents are ultimately accessible through the Freedom of Information Act. 6
The United States is the most transparent of the nuclear-armed states.
It is one of only a small handful of countries that has published historical and current data about the exact size of its nuclear stockpile. [1, 2, 3] In addition, the United States discloses detailed information regarding its current stockpile, nuclear-capable delivery vehicles, missile launches, deployment numbers and locations, nuclear doctrine, and modernization plans, among other key elements. [4, 5, 6, 7]
This high degree of transparency is primarily due to several factors:
The United States’ participation in arms control and risk reduction treaties (e.g. New START, which limits deployments of strategic warheads and launchers, and the 1988 agreement on the pre-notification of ballistic missile launches) that require and encourage notifications and disclosures. [8, 9]
The requirement of the Departments of Defense and Energy to justify funding requests to Congress, which can in turn interrogate and request additional information through update, testimony, or study. [10, 11, 12]
The United States’ robust watchdog, civil society, and media landscape, including government-funded agencies like the Government Accountability Office and the Congressional Budget Office, investigative journalists, and nongovernmental organizations that report on, request comment from, and critique government programs and plans. [13, 14]
A legacy culture of responsible transparency and open government, supported by legal mechanisms like the Freedom of Information Act, which allow researchers to access certain details about nuclear programs that would otherwise be classified.
A desire to contrast its own nuclear program with those of its less-transparent competitors, like Russia or China. [15, 16]
A belief that, as the National Nuclear Security Administration stated in 2024, that “Increasing the transparency of states’ nuclear stockpiles is important to nonproliferation and disarmament efforts, including commitments under the Nuclear Non-Proliferation Treaty, and efforts to address all types of nuclear weapons, including deployed and non-deployed, and strategic and non-strategic.” [3, 16]
Despite the United States’ relatively high degree of transparency regarding its nuclear forces, in recent years it is clear that the efforts have been made to curtail some of these elements. For example:
The United States is increasingly keeping secret more details about its nuclear forces. 17 For example, for many years the majority of the budget and characteristics of the upcoming B-21 Raider––the Air Force’s new nuclear-capable stealth bomber––were classified. 18
Since 2019, the United States has stopped declassifying the size of its nuclear stockpile and its number of dismantled warheads on an annual basis, instead electing to release this data on an ad hoc basis. 19 The denial of declassification requests in 2023 included the justification that “the Department of Defense and Department of Energy/National Nuclear Security Administration do not believe that [it] is in the best interest of the United States,” but did not provide any additional details. 20
The United States has selectively removed or omitted certain sensitive details from official documents after widespread public reporting and critique. For example, in the North Atlantic Treaty Organization’s Security Investment Program budget for Fiscal Year 2023, the U.S. Department of Defense included “the UK” among a list of countries slated for infrastructure modernization at “special weapons” storage sites––thus indicating the potential return of U.S. nuclear weapons to UK soil for the first time in 15 years. 21 Following an influx of scrutiny, the following year’s budget document for the same program did not include any country names. 22
Following Russia's unilateral suspension of New START in February 2023, the United States disclosed one final set of deployment-related treaty data from March 2023, but subsequently has not released any deployment data since then. [8, 23]
Traditionally, each successive U.S. presidential administration issues a Nuclear Posture Review (NPR) that describes U.S. nuclear strategy, policy, posture, and forces. The most recent iteration of the U.S. Nuclear Posture Review, issued in 2022 by the Biden administration, reaffirmed longstanding policy that “the United States will not use or threaten to use nuclear weapons against non-nuclear weapon states that are party to the NPT [Treaty on the Non-Proliferation of Nuclear Weapons] and in compliance with their nuclear non-proliferation obligations.” 1
While this language does not specifically reference Iran by name, Iran is the country that most accurately meets this description. The NPR states that “U.S. policy is to prevent Iran from acquiring a nuclear weapon,” 1 and the most recent iteration of the U.S. Nuclear Employment Strategy––issued in 2024––states that the United States “is prepared to use all elements of national power to ensure that outcome.” 2 In June 2025, the International Atomic Energy Agency (IAEA) issued a resolution finding that Iran was no longer in compliance with its NPT obligations. 3
Traditionally, each successive U.S. presidential administration issues a Nuclear Posture Review (NPR) that describes U.S. nuclear strategy, policy, posture, and forces. The most recent iteration of the U.S. Nuclear Posture Review, issued in 2022 by the Biden administration, reaffirmed longstanding policy that the United States “maintains a very high bar for nuclear employment,” and “would only consider the use of nuclear weapons in extreme circumstances to defend the vital interests of the United States or its Allies and partners.” 1 However, the United States has traditionally not provided any specific details as to what constitute “vital interests.”
This guidance was translated into the most recent iteration of the Nuclear Employment Strategy, which was issued in November 2024 and repeats the above lines verbatim. 2
In addition, U.S. nuclear declaratory policy leaves the door open for nuclear first-use, as the most recent NPR indicated that the adoption of such a policy “would result in an unacceptable level of risk in light of the range of non-nuclear capabilities being developed and fielded by competitors that could inflict strategic-level damage to the United States and its Allies and partners.” 1 The Nuclear Employment Strategy elaborates on this further, noting that the United States “does not depend on a launch-under-attack policy to ensure a credible response.” 2
In a shift from previous guidance, the 2022 guidance requires the Department of Defense to “assess the ability of non-nuclear capabilities to contribute to deterrence, and [...] integrate these capabilities into operational plans, as appropriate.” This is being done “to advance the goal of reducing reliance on nuclear weapons [...].” 1
The United States issues advance notice of long-range missile tests, space launch activities that might be mistaken for nuclear missile launches, and military exercises involving nuclear and dual-capable weapon systems, through three main avenues:
The United States issues notifications of launches of intercontinental ballistic missiles and submarine-launched ballistic missiles pursuant to a 1988 bilateral treaty between the United States and Russia. These notifications include the area from which the launch will take place, the geographic coordinates of the planned impact area or areas of the reentry vehicles, and must be issued no less than 24 hours in advance of launch. However, these notifications are issued through the National Nuclear Risk Reduction Centers of the two countries and are not disclosed publicly. In addition, they do not cover shorter-range missile launches. 1
The United States regularly issues press releases in advance of its long-range missile launches and nuclear weapons exercises, as these are typically planned months or years in advance and correspond to a rigorous testing schedule. For example, on November 3rd, 2025, Vandenberg Space Force Base issued a press release stating that “An operational test launch of an Air Force Global Strike Command unarmed Minuteman III intercontinental ballistic missile is scheduled between 11:01 p.m. to 5:01 a.m. Pacific Time, Nov. 4, from north Vandenberg.” 2
The United States issues regular navigational warnings to airmen and mariners for each missile and rocket test that it conducts, pursuant to the Convention on International Civil Aviation and and in support of the Global Maritime Distress and Safety System, and provides specific information about the nature of the launch, the coordinates of the launch and impact areas, and the dates under which the warning remains in effect. However, these warnings do not indicate what type of missile is being launched. 3
Traditionally, each successive U.S. presidential administration issues a Nuclear Posture Review (NPR) that describes U.S. nuclear strategy, policy, posture, and forces. The policies articulated in the most recent NPR––published in 2022––were translated into an updated version of the U.S. Nuclear Employment Strategy, which was published in 2024.
The guidance included in both documents explicitly noted that the role of U.S. nuclear weapons is to deter strategic attack, which explicitly include “significant, high-consequence, non-nuclear attack[s] that ha[ve] strategic-level effect[s]” alongside nuclear attacks at any scale. [1, 2] While these terms were not defined in the 2022 NPR, they were defined in the previous 2018 NPR, as follows: Significant non-nuclear strategic attacks include, but are not limited to, attacks on the U.S., allied, or partner civilian population or infrastructure, and attacks on U.S. or allied nuclear forces, their command and control, or warning and attack assessment capabilities.” 3 The 2018 NPR also lists “chemical, biological, cyber, and large-scale conventional aggression” as examples of “non-nuclear strategic threats.” 3
The United States is the only country to periodically disclose the size of its current nuclear stockpile, the number of annually dismantled warheads, and the approximate number of retired warheads awaiting dismantlement. It did this for the first time in 2010, when the Obama administration declassified the entire history of the US nuclear stockpile, including the annual stockpile size, the number of dismantled warheads since 1994, and the number of retired warheads awaiting dismantlement. 4 The United States continued to disclose these data on an annual basis until 2019, when the US Department of Defense denied successive declassification requests until 2021, when transparency was restored and the figures from the missing years were disclosed. [5, 6] Another disclosure of these figures was made in 2024, similarly restoring the previous years' missing data. 1 It appears that the United States is shifting towards disclosing these figures on an ad hoc, rather than annual, basis.
In addition, as a party to New START––a bilateral treaty between the United States and Russia limiting numbers of deployed strategic warheads and launchers––the United States released its aggregate numbers of strategic warheads on deployed intercontinental ballistic missiles, submarine-launched ballistic missiles, and nuclear warheads counted for deployed heavy bombers on a biannual basis throughout most of the duration of the treaty. 2 Although it did not publish the disaggregated data, this data was available upon request from the Department of State throughout this time. Following Russia's unilateral suspension of New START in February 2023, the United States disclosed one final set of deployment-related treaty data from March 2023, but subsequently has not released any deployment data since then. 3
The United States does not disclose the exact yields of the warheads in its current arsenal. However, it does occasionally disclose information about current warheads that would help analysts make educated assumptions about their yields, particularly by disclosing information about warhead designs or yields relative to other weapons. For example, in its announcement describing the development of the new B61-13 gravity bomb, the Department of Defense stated that the weapon would "have a yield similar to the B61-7, which is higher than that of the B61-12." 1
The United States has also declassified the exact yields of many of its nuclear tests, as well as the yields of some nuclear weapons that are no longer in the US arsenal. [2, 3, 4] For example, the yield of the B53––once the highest-yield nuclear weapon in the US arsenal––was officially declassified in 2014 and revealed to be 9 megatons, although it had already been retired and dismantled by that time. 5 In addition, the United States has declassified the total megatonnage in its arsenal between 1945 (0.04 megatons) and 1994 (2,375.3 megatons); the year of the largest stockpile megatonnage was 1960 (20,491.17 megatons). 6 While this dataset was not disaggregated by weapon, it can be used to make analytical estimates for individual warheads.