Assessing the state of U.S. nuclear weapons capabilities presents several challenges. First, the U.S. has elected to maintain the weapons—based on designs from the 1970s—that were in the stockpile when the Cold War ended rather than develop new weapons. Second, detailed data about the readiness of nuclear forces, their capabilities, and weapon reliability are not publicly available, and this makes analysis difficult. Third, the U.S. nuclear enterprise is comprised of many components, some of which are also involved in supporting conventional missions. For example, bombers do not fly with nuclear weapons today as they routinely did during the Cold War (although they are capable of doing so again if the decision should ever be made to resume this practice). Also, the U.S. National Nuclear Laboratories perform a variety of functions related to nuclear nonproliferation, medical research, and nuclear detection, among many others, as opposed to focusing solely on the nuclear weapons mission.
Thus, assessing the extent to which any one piece of the nuclear enterprise is sufficiently funded, focused, and effective with regard to the nuclear mission is problematic.
The second important factor is flexibility and resilience of the nuclear weapons complex that underpins the U.S. nuclear deterrent. If the U.S. detects a game-changing nuclear weapons development in another country, the capability of the U.S. nuclear weapons complex to adjust would be of concern.
The U.S. does maintain an inactive stockpile that includes near-term hedge warheads that can be put back into operational status within six to 24 months.1 Extended hedge warheads can be made ready within 24 to 60 months.2 The U.S. preserves some of this upload capability on its strategic delivery vehicles. For example, the U.S. Minuteman III ICBM can carry up to three nuclear warheads, though it is currently deployed with only one.3
Presidential Decision Directive-15 (PDD-15) requires the U.S. to maintain the ability to conduct a nuclear test within 24 to 36 months of a presidential decision to do so.4 However, successive governmental reports have found continued deterioration of technical and diagnostics equipment and an inability of the National Nuclear Laboratories to fill technical positions supporting nuclear testing readiness.5
The National Nuclear Laboratories are beset by talent and recruitment challenges of their own. Thomas D’Agostino, former Under Secretary of Energy for Nuclear Security and Administrator of the National Nuclear Security Administration (NNSA), stated that in about five years, the United States will not have a single active engineer who had “a key hand in the design of a warhead that’s in the existing stockpile and who was responsible for that particular design when it was tested back in the early 1990s.”6 This is a significant problem because for the first time since the dawn of the nuclear age, the U.S. will have to rely on the scientific judgment of people who were not directly involved in nuclear tests of weapons that they had designed and developed and were certifying. It is unclear how much of the existing inactive stockpile will go through the life extension program. Hence, our ability to reconstitute nuclear forces will probably decline with the passage of time.
The uncertainty regarding the funding and direction of the nuclear weapons complex is one of the factors that complicate the National Laboratories’ efforts to attract and maintain young talent. The shift of focus away from the nuclear mission after the end of the Cold War caused the National Laboratories to lose their sense of purpose and to feel compelled to reorient their mission focus and change their relationship with the government. The NNSA was supposed to address these problems, but it has largely failed in this task, partly because “the relationship with the NNSA and the National security labs appears to be broken.”7
In 1999, the Commission on Maintaining U.S. Nuclear Weapons Expertise concluded that 34 percent of the employees supplying critical skills to the weapons program were more than 50 years old. The number increased to 40 percent in 2009.8 This is more than the average in the U.S. high-technology industry.9 In 2012, a number of employees of the Los Alamos National Laboratory were laid off in anticipation of a $300 million shortfall.10 The lack of resources is undermining the morale of the workforce.
The third important indication of the health of the overall force is the readiness of forces that actually operate U.S. nuclear systems. Since the end of the Cold War, the Air Force, which currently operates two of the three legs of the nuclear triad, has faced significant challenges regarding its operation of U.S. nuclear forces. In 2006, the Air Force mistakenly shipped ICBM components to Taiwan.11 A year later, the Air Force transported nuclear-armed cruise missiles without authorization (or apparently even awareness that it was doing so) across the U.S.12 These serious incidents led to the establishment of a Task Force on DOD Nuclear Weapons Management, which found that “there has been an unambiguous, dramatic, and unacceptable decline in the Air Force’s commitment to perform the nuclear mission and, until very recently, little has been done to reverse it” and that “the readiness of forces assigned the nuclear mission has seriously eroded.”13
Following these incidents, the Air Force instituted broad changes to improve oversight and management of the nuclear mission and inventory of nuclear weapons, including creating the Global Strike Command to organize, train, and equip intercontinental-range ballistic missile and nuclear-capable bomber crews as well as other personnel to fulfill a nuclear mission and implement a stringent inspections regime.
The U.S. government currently uses two metrics to evaluate the Department of Defense’s Strategic Objective of “Maintain[ing] a safe, secure, and effective nuclear arsenal to deter attack on the U.S. and on our allies and partners.”14 They are:
“[The] Number of formal Department of Defense-led meetings with international partners to reaffirm U.S. commitments to extended deterrence” and
“[The] Passing percentage rate for Defense Nuclear Surety Inspections (DNSIs).”15
In the first category, the Department of Defense exceeded its goals in FY 2011, FY 2012, and FY 2013. In the second category, passing percentage rates were 71 percent in FY 2008, 77 percent in FY 2009, 73 percent in FY 2010, 85.7 percent in FY 2011, 100 percent in FY 2012, and 91.7 percent in FY 2013, with the target being 100 percent. While these indicate an improved trend, the Air Force is currently undergoing a major review following a string of additional missteps in 2013 and 2014.16
This calls the credibility and relevance of the metrics into question. It is also not clear how the number of meetings contributes to affirming the U.S. commitment to extended deterrence absent evaluation of capabilities and requirements that allies consider necessary for assurance.
Fiscal uncertainty and a steady decline in resources for the nuclear weapons enterprise have negatively affected U.S. nuclear weapons readiness. Admiral C. D. Haney, Commander, U.S. Strategic Command (STRATCOM), recently testified that “[i]n recent years the percentage of spending on nuclear forces has gradually declined to only 2.5% of total DOD spending in 2013—a figure near historic lows,”17 although he also stated that he fully believes STRATCOM “remains capable and ready to meet our assigned missions.”
Admiral Haney went on to note that the sequestration-level reductions in FY 2013 had negatively affected STRATCOM’s readiness and had the potential to further affect U.S. capabilities in the future. While he noted that it was impossible to tell just what effects sequestration would have, he observed that the existing freeze on hiring new personnel and furlough of the workforce during the summer of 2013 had diminished the human capacity needed, resulting in a lessening of STRATCOM’s readiness through lack of research and development, modernization, and know-how.
Implications for U.S. National Security
U.S. nuclear forces are not designed to shield the nation from all types of attacks from all adversaries. They are designed to deter large-scale attacks, including nuclear attacks, against the U.S. homeland, forward-deployed troops, and allies.
In addition, U.S. nuclear forces have played an important role in the global nonproliferation regime. U.S. assurances to NATO, Japan, and South Korea have led these allies either to keep the number of their nuclear weapons lower than otherwise would be the case (France, the U.K) or to forgo their development and deployment altogether. North Korea has proven that a country with very limited intellectual and financial resources can develop a nuclear weapon if it decides to do so. This makes U.S. nuclear assurances for advanced industrial nations ever more important.
Certain negative trends could undermine U.S. nuclear deterrence if problems are not addressed. From an aging nuclear weapons infrastructure and workforce, to the need to recapitalize all three legs of the nuclear triad, to the need to conduct life extension programs while maintaining a self-imposed nuclear weapons test moratorium, to limiting the spread of nuclear know-how and the means to deliver nuclear weapons, to adversaries who are modernizing their nuclear forces, there is no shortage of challenges on the horizon.
Deterrence is a complex interplay between one’s conventional and nuclear forces and the beliefs of both allies and adversaries that one will use these forces to protect allies and defend both one’s own interests and their interests. The requirements of deterrence and warfighting may be quite different and thus should be considered within their own context and then balanced against each other to ensure that the U.S. nuclear portfolio is structured in capacity, capability, variety, and readiness to meet both types of demands. In addition, military requirements and specifications for nuclear weapons might be different depending on different circumstances and who one wants to deter from doing what.
Due to the complex interplay between policy, actions that states take in international relations, and other actors’ perceptions of the world around them, it is quite possible that one might never know precisely when deterrence became less credible. Nuclear weapons capabilities take years to develop, and the infrastructure supporting them takes years to deteriorate. But we can be reasonably certain that a robust, well-resourced, focused, and reliable nuclear enterprise is more likely to sustain its deterrent value than is a weakened, unfocused, and questionable one.
We know that the U.S. is capable of incredible mobilization when dangers materialize. The evidence points to just such a danger maturing on our doorstep with regard to nuclear affairs. The nuclear threat environment is dynamic and proliferating, with old and new actors developing new capabilities while the U.S. enterprise is moribund. This is a worrisome situation because of its implications both for the security of the United States and for the security of its allies and the free world generally.
- Chapter 3, “U.S. Nuclear Forces,” in U.S. Department of Defense, Office of the Secretary of Defense, Office of the Assistant Secretary of Defense for Nuclear, Chemical, and Biological Programs, The Nuclear Matters Handbook, Expanded Edition, 2011, (accessed September 17, 2014). [↩]
- Ibid. [↩]
- George C. Marshall Institute, “LGM-30G Minuteman III,” Missile Threat website, (accessed September 30, 2014). [↩]
- “Test Readiness,” in Chapter 1, “Safety, Security, and Reliability of the U.S. Nuclear Weapons Stockpile,” in Committee on Reviewing and Updating Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty; Policy and Global Affairs; National Research Council, The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States (Washington: National Academies Press, 2012), (accessed September 17, 2014). [↩]
- U.S. Department of Energy, Office of Inspector General, Memorandum, “Report on the Follow-up Audit of the Test Readiness at the Nevada Test Site,” Audit Report No. OAS-L-10-02, October 21, 2009, (accessed September 17, 2014). [↩]
- Kate Brannen, “Nuke Expert Pool Shrinking,” Defense News, April 14, 2012, (accessed September 17, 2014). [↩]
- Statement of Dr. Charles V. Shank, Senior Fellow, Howard Hughes Medical Institute, and Co-chair, National Research Council Committee on Review of the Quality of the Management and of the Science and Engineering Research at the DOE’s National Security Laboratories–Phase 1, Hearing to Receive Testimony on National Nuclear Security Administration Management of Its National Security Laboratories, Subcommittee on Strategic Forces, Committee on Armed Services, U.S. Senate, April 18, 2012, (accessed September 30, 2014). [↩]
- Task Force on Leveraging the Scientific and Technological Capabilities of the NNSA National Laboratories for 21st Century National Security, Leveraging Science for Security: A Strategy for the Nuclear Weapons Laboratories in the 21st Century, Henry L. Stimson Center Report No. 71, March 2009, p. 11, (accessed September 17, 2014). [↩]
- Ibid. [↩]
- Ambassador C. Paul Robinson, John Foster, and Thomas Scheber, “The Comprehensive Test Ban Treaty: Questions and Challenges,” Heritage Foundation Lecture No. 1218, November 7, 2012. [↩]
- Associated Press, “US Mistakenly Ships ICBM Parts to Taiwan,” March 25, 2008, (accessed September 17, 2014). [↩]
- Associated Press, “Air Force Official Fired After 6 Nukes Fly Over US,” updated September 5, 2007, (accessed September 17, 2014). [↩]
- U.S. Department of Defense, Secretary of Defense Task Force on DoD Nuclear Weapons Management, Report of the Secretary of Defense Task Force on DoD Nuclear Weapons Management: Phase I: The Air Force’s Nuclear Mission, September 2008, (accessed September 17, 2014). [↩]
- Chapter 8, “Performance Improvement,” in U.S. Department of Defense, United States Department of Defense Fiscal Year 2015 Budget Request: Overview. [↩]
- These are Air Force bases and Navy ports inspections conducted by the Defense Threat Reduction Agency. For more information, see Defense Threat Reduction Agency and USSTRATCOM Center for Combating WMD and Standing Joint Force Headquarters–Elimination, “Nuclear Surety Inspections,” (accessed September 17, 2014). [↩]
- For more detailed information, see Associated Press, “Key Findings in AP Nuclear Missile Corps Probe,” May 22, 2014, (accessed September 17, 2014). [↩]
- “Statement of Admiral C. D. Haney, Commander, United States Strategic Command, Before the Senate Committee on Armed Services,” February 27, 2014, (accessed September 17, 2014). [↩]