Priority of Hard and Deeply Buried Target Defeat

TOPIC SPONSOR: AF/A10C

What priority should a Hard and Deeply Buried Target (HDBT) defeat capability take within U.S. nuclear strategy? How important is it that U.S. nuclear forces continue to be able to deny adversary sanctuary and hold critical protected targets at risk for each of these countries? Is there any potential adversary that finds this capability either critically influential or irrelevant in their decision calculus? What role should an HDBT defeat capability play, if any, in U.S. employment strategy?

• Blain, Maj. Aaron P., "Beyond Bunker Busting: Airpower in the Underworld," AFGC thesis, 2023, 44 pgs.  
  • ​​​​​​​Addresses the proliferation of underground facilities by adversaries like Russia, China, North Korea, and Iran, who use them as sanctuaries to protect critical military capabilities. Rather than defining a role for HDBT defeat within nuclear strategy, Blain argues that the U.S. must innovate beyond both precision kinetic bombing and nuclear ordnance because adversaries are continuously building deeper, more resilient structures. To successfully hold these protected targets at risk and deny adversary sanctuary, the paper recommends that U.S. employment strategy shift toward functional, non-kinetic defeat options—specifically by utilizing unmanned systems, communication mesh networks, and mobile data processing to disrupt the industrial control systems (such as blast doors, power, and air) of these facilities without resorting to nuclear strikes.
• Dougherty, Maj. Matthew J., "The Dragon's Tail: Deterring China in an Era of Maneuverable Hypersonic Weapons," ACSC paper, 2022, 90 pgs. 
  • Highlights how emerging Maneuverable Hypersonic Weapons (MHWs) can provide a penetrating capability against deeply-buried underground facilities (DBUFs). The paper argues that dual-use (conventional or nuclear) MHWs provide an exotic, worldwide offensive capability that is ideally suited for striking time-sensitive, high-value targets housed in DBUFs. In U.S. employment strategy, utilizing MHWs allows the military to hold these critical protected targets at risk even within highly contested Anti-Access/Area Denial (A2/AD) environments, effectively bypassing the need for traditional nuclear weapons to accomplish the same strategic attack objectives.
• Douglas, Jamie, "Dealer's Choice: The Likelihood of Multilateral Treaties, Bilateral Treaties or a Nuclear Arms Race," SAASS thesis 2021, 106 pgs. 
  • Answers the question by tracing how U.S. strategy regarding Hard and Deeply Buried Targets (HDBTs) evolved through the 1994 and 2002 Nuclear Posture Reviews (NPRs) to deny adversaries underground sanctuary. The paper explains that because over 70 countries rely on underground facilities, creating sanctuaries the U.S. lacked the ability to destroy, locating and defeating HDBTs became a critical requirement for national security. However, rather than prioritizing this capability within nuclear strategy, the 1994 NPR emphasized developing conventional capabilities to replace nuclear weapons for this role, shifting away from viewing low-yield nuclear weapons as the solution for holding protected WMD threats at risk. By the 2002 NPR, the U.S. aimed to resolve intelligence shortfalls in characterizing HDBTs so that conventional forces could safely assume the deterrence and employment roles previously held by nuclear bunker-busters.
• Kerns, Maj. Ryan O., "Strategy in the Automation Age: Strategic Weapons Theory and Hypersonic Implications," SAASS thesis, 2023, 114 pgs. 
  • Partially addresses the prompt by explaining how holding deeply buried targets at risk impacts adversary decision calculus, though it emphasizes the use of conventional hypersonic weapons rather than nuclear forces. Kerns argues that the speed and precision of modern hypersonic weapons create new employment opportunities to hold "highly mobile, deeply buried, and protected targets" at risk, effectively denying sanctuaries that adversaries previously considered safe from major or nuclear conflict. By credibly threatening these protected targets conventionally, the U.S. can compress an adversary's decision-making cycle and manage escalation control at lower conflict thresholds, fulfilling a strategic deterrence role that reduces the nation's reliance on nuclear escalation.
• McGonegal, Maj. Jack, "High Power Microwave Weapons: Disruptive Technology for the Future," ACSC ACTS 2.0 RTF, 2020, 20 pgs.  
  • Proposes High Power Microwaves (HPMs) as a non-kinetic defeat capability that borrows from historical nuclear "countervalue" targeting concepts to affect an adversary's decision calculus. Rather than physically destroying a bunker with massive explosives, the paper explains that HPMs can defeat HDBTs by penetrating "airshafts, power cabling, heating, ventilation, and air conditioning (HVAC) surface ducts and access architecture". By transmitting microwave energy through these physical vulnerabilities, HPMs can bypass the facility's hardening to destroy the vital electronic systems and command and control nodes stored inside. The author argues that utilizing HPMs provides the U.S. with a flexible force multiplier to covertly or overtly coerce adversaries and hold their most critically protected assets at risk without causing the widespread collateral damage associated with traditional kinetic or nuclear strikes.
• Scott-Deleon, Jonathan D., "The Great Flying Fleet: The Bomber's Conventional Role in the 21st Century Air Force," SAASS thesis, 2021, 114 pgs.  
  • Addresses HDBT defeat capabilities as a catalyst for conventional weapons development rather than a nuclear strategy. The paper explains that during the Gulf War, the need to destroy HDBTs led the Air Force to rapidly develop, test, and employ the GBU-28 precision-guided munition in less than three weeks. The author highlights that successfully delivering this highly accurate conventional weapon from an F-111 to destroy the al-Taji command and control bunker proved that a single weapon could achieve the desired strategic effect, which ultimately "negated the tactical need for the heavy bomber to destroy HDBT".
• Varilek, Lt. Col. John D., "United States Hypersonic Weapons and China Deterrence Effects," AWC SSP, 2019, 38 pgs. 
  • Examines how HDBT mitigation fits into the Conventional Prompt Global Strike (CPGS) doctrine and affects the decision calculus of potential adversaries like China. The paper identifies HDBT defeat as a key mission set for U.S. hypersonic weapon development, which provides the ability to hold previously secure underground targets at risk without crossing the nuclear threshold. Regarding adversary decision calculus, the author notes that China may find these penetrating capabilities highly threatening; because hypersonic weapons blur the lines between conventional and nuclear strikes, using them to threaten Chinese protected targets could inadvertently destabilize the deterrence status quo and provoke an unintended nuclear escalation.