Three Reasons Why the U.S. Needs a Replacement Nuclear Cruise Missile

Three Reasons Why the U.S. Needs a Replacement Nuclear Cruise Missile
Three Reasons Why the U.S. Needs a Replacement Nuclear Cruise Missile
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Former Secretary of Defense William Perry and former Assistant Secretary of Defense Andy Weber argue in an October op-ed that the new Long Range Standoff (LRSO) cruise missile program is both unnecessary and potentially destabilizing.  Several follow-up pieces, as well as a series of congressional op-eds, largely echo these same arguments.  On the other side of the issue, several response articles and a letter from the Air Force Association contend that the original op-ed misunderstands LRSO’s role within the U.S. deterrent and misinterprets relevant history on the topic of strategic stability

In response to this ongoing debate, this article provides a brief overview of why LRSO is both vital to U.S. deterrence posture and an indispensable tool for maintaining stability in a dynamic strategic environment.  There are three main reasons why LRSO is critical to national defense.

A Unique Option

First, nuclear cruise missiles are a unique option for deterring nuclear escalation.  Two important trends support this assertion.  The first is the rise of Anti-Access Area Denial (A2AD) technologies and techniques.  A2AD attempts to raise the costs of intervention in a given conflict by holding U.S. aircraft, ships, and forward bases at risk.  Should an A2AD-equipped adversary threaten the United States with nuclear escalation, LRSO affords the President a tailorable deterrence option capable of penetrating enemy air defenses without a prolonged operation to degrade A2AD systems.  This capability is unique because no penetrating bomber can be as survivable against heavily defended targets as a low-observable cruise missile.  Importantly, the combination of bomber penetration and missile range also prevents potential adversaries from sheltering high-value deterrence targets beyond the operational range of U.S. bombers.  These standoff weapon attributes enhance the credibility of the U.S. strategic and extended deterrence policies that A2AD attempts to undermine.

The second trend is the increasing interest in “escalate to de-escalate” strategies.  These strategies attempt to level the playing field with the United States by threatening limited nuclear use in the face of failed conventional aggression.  In this type of scenario, the task of senior military commanders is to provide the President with options for deterring and, if necessary, responding to adversary nuclear use.  This intricate process of linking military ways and means with political ends is ultimately facilitated by the strength of the Triad.  The Triad ensures that senior military leaders, as one component in a whole-of-government approach, have the right tools to offer the President under the most extreme scenarios.  Nuclear cruise missiles play a critical role in this process.

It is traditionally said that the Intercontinental Ballistic Missile leg offers responsiveness, the Submarine-Launched Ballistic Missile leg ensures survivability, and the air leg provides flexibility to the U.S. deterrent.  In broad terms, these are accurate and useful characterizations.  As I have written elsewhere, there is deterrence value in publically categorizing the contributions of each leg in somewhat general terms.  However, these characterizations do not constrain the usefulness of each leg across the spectrum of potential escalation scenarios.  In practice, each Triad leg has highly contextual advantages in responsiveness, survivability, and flexibility when applied to a given crisis. 

In escalation scenarios, the true deterrence value of the Triad as a whole resides in offering tailorable tools that leave the adversary with no doubt that the United States has the right means to underwrite the President’s deterrence objectives.  By maintaining the air leg of the Triad’s effectiveness as depicted above, LRSO provides unique degrees of responsiveness, survivability, and flexibility to meet the President’s intent.  In this sense, not having the deterrence attributes provided by a nuclear cruise missile is potentially destabilizing in the important strategic context of nuclear escalation.

A recent New York Times article discusses the view that current nuclear modernization initiatives, such as LRSO, may lower the threshold for nuclear weapons use by lowering collateral damage effects.  This mischaracterizes the impact of LRSO on deterrence in today’s strategic environment.  By negating A2AD techniques and addressing potential escalation strategies, LRSO bolsters the overall credibility of the U.S. deterrent across the full spectrum of scenarios making the unthinkable even more unthinkable.  This assures American allies of U.S. extended deterrence commitments and, in the process, discourages further proliferation of indigenous nuclear capabilities.      

A Vital Hedge

The second reason LRSO is so important is nuclear cruise missiles hedge against technical and operational uncertainty.  The entire nuclear Triad is aging and this has two main implications.  First, the likelihood of unforeseen technical issues with any leg of the Triad is increased.  Second, potential adversaries will continue to research defeat strategies for current Triad systems.  Should unexpected technical or operational vulnerabilities arise with another leg of the Triad, the ability to rapidly upload bombers with nuclear-armed cruise missiles will be critical to maintaining the viability of the U.S. strategic deterrent. 

Utilizing LRSO in this capacity allows the United States to optimize the streamlined bomber force of the New START Treaty construct by leveraging the “bomber accounting rule.”  By design, this rule allows each side to count individual bombers as one deployed warhead regardless of how many weapons it actually carries.  This hedging role serves as a sort of insurance policy, providing the United States with an important means for ensuring strategic stability should another leg of the Triad encounter unforeseen problems. 

A Needed Replacement

The final reason LRSO is so vital is that the current Air Launched Cruise Missile (ALCM) arsenal is aging out and facing a steadily improving A2AD threat.  ALCM was fielded in 1982 with a projected service life of 10 years.  Robust sustainment efforts have effectively extended ALCM’s service life by over two decades but depletion due to annual testing requirements will eventually bring the ALCM inventory below required levels. 

One follow-up article to the Perry/Weber op-ed argues that if the LRSO program continues it should be delayed to allow the U.S. time to seek international opinions on its role within regional deterrence architectures.  This assertion underestimates the robust and ongoing dialogue maintained by the U.S. with its deterrence partners.  It also fails to realize the urgency of the program.  LRSO’s development timeline is designed to prevent a potential shortfall as ALCM exits the inventory.  It is critical that LRSO and its associated warhead program remain adequately funded and carefully synchronized in order to prevent a capability lapse. 

Another set of articles question the need to replace ALCM on the grounds that modern conventional cruise missiles, such as the Joint Air-to-Surface Standoff Missile Extended-Range or JASSM-ER, can cover the mission set proposed for LRSO.  This assumes, incorrectly, that LRSO is a warfighting weapon intended to accomplish missions, such as defense suppression, currently filled by conventional weapons.  Fundamentally, this argument misunderstands why a survivable nuclear cruise missile is so important.  LRSO increases the credibility of U.S. nuclear deterrence by negating air defense systems via low-observable characteristics and thereby holding deterrence targets at risk.  It is not intended as a nuclear equivalent to current conventional counter-air defense systems.


In sum, preserving today’s air-delivered nuclear standoff capability is vital to deterring potential aggression and assuring key allies.  Nuclear cruise missiles provide a unique deterrence option to the President and serve as a hedge against unforeseen technical or operational vulnerabilities in the nuclear Triad.  The LRSO program and its associated warhead life extension program are crucial to maintaining this capability and must be fully supported in order to produce an ALCM replacement before a potentially de-stabilizing capability loss develops.

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