Cruise Control: Why the U.S. Should Not Buy a New Nuclear Air-Launched Cruise Missile


The Obama administration’s fantastical plan to modernize the Cold War-era nuclear triad of land-based missiles, submarine-launched missiles, and long-range bombers is prompting an increasingly loud and much-needed debate in Washington and beyond about whether the effort is necessary and sustainable.

One of the most controversial pieces of this “all of the above” sustainment approach, which is projected to exceed $350 billion over the next decade, is the Air Force’s proposal to build a new fleet of roughly 1,000 nuclear-capable air-launched cruise missiles (ALCMs).

The Defense Department and supporters of replacing the nuclear ALCM in Congress and the think tank community argue that building a new missile is necessary to maintain an effective U.S. nuclear deterrent because the current missile is losing its ability to penetrate increasingly sophisticated air and missile defenses. These proponents also claim that retaining an ALCM option for the bomber leg of the triad provides the president with unique options to control escalation and respond proportionally to a limited nuclear attack. In other words, the new missiles would augment the ability of the U.S. military to fight a nuclear war.

In the halls of the Pentagon, where planners have spent decades justifying nuclear force levels that would make a hoarder seem frugal by comparison, these arguments have taken on an almost religious quality. Yet strip away the magical thinking that permeates so much of U.S. nuclear strategy and the case for a new ALCM is weak: it is redundant, recklessly expensive, and potentially destabilizing.


ALCMs, which are currently carried by the B-52H long-range bomber, are guided missiles that can attack targets at distances outside the range of air defense systems. They were developed at a time when America did not have stealth bombers and sought an additional nuclear system with which to deter and impose costs on the Soviet Union.

America’s lone remaining ALCM variant is the AGM-86B, with a range of 1,500-plus miles. Multiple life-extension programs have kept the missile, which was first fielded in 1982 with a planned service life of 10 years, in service for more than 30 years. The Air Force is planning to retain the missile until 2030.

The Air Force is developing the long-range standoff cruise missile (LRSO) to replace the existing ALCM. The new missile will be compatible with existing B-2 and B-52 bombers, as well as with the planned B-21 bomber. The first missile is slated for production by 2026. Including the refurbished warhead that would be carried by the missile, the new weapon system is currently estimated to cost roughly $20 to $30 billion to acquire.

The LRSO is not the first time the Pentagon has sought to upgrade its nuclear ALCM capabilities. During the early 1990s, the Air Force developed the Advanced Cruise Missile, describing it as a “subsonic, low-observable air-to-surface strategic nuclear missile with significant range, accuracy, and survivability improvements over the ALCM.”

However, after spending $6 billion to buy and operate roughly 450 missiles, the George W. Bush administration announced the retirement of the system in 2008 due to major performance and reliability issues. The Pentagon hopes that the same fate that befell the ACM will not befall the LRSO.

A redundant capability

While supporters of the LRSO cite anticipated improvements in the air defenses of potential adversaries as a reason to develop the new nuclear cruise missile, it is doubtful that any target the missile could hit could not also be destroyed by other U.S. nuclear weapons or conventional cruise missiles.

For starters, the LRSO weapon is just one element of the Air Force’s plan for the air-based leg of the triad.

The service is planning to spend over $100 billion to build 80 to 100 new stealthy penetrating strategic bombers. One of the top rationales for building a new bomber is to extend America’s air dominance in advanced air defense environments. In addition to carrying the LRSO, the new long-range strike bomber (B-21) will be armed with refurbished B61 mod 12 nuclear gravity bombs. Upgrading the B61 is expected to cost roughly $10 billion. The B-21 is scheduled to remain in service for 50 years while the B61 mod 12 is expected to last 20-30 years.

LRSO proponents respond to this point by arguing that future air defenses could jeopardize unchallenged U.S. bomber operations in certain theaters. Though supporters do not claim that the LRSO would be inherently more survivable than the B-21, they claim that the LRSO would increase the number of penetrating targets each bomber presents to an adversary. But in the event the B-21 can’t reach a target with a gravity bomb, the weapons associated with the other two legs of the nuclear triad, submarine-launched ballistic missiles (SLBMs) and intercontinental ballistic missiles (ICBMs), can penetrate air defenses and strike targets anywhere on the planet with high confidence.

Indeed, in making the case for the LRSO, supporters often ignore the other two legs of the triad altogether.

As if this wasn’t head-scratching enough, some sources say there are significant restrictions on the use of the existing ALCM due to aging and reliability issues. This raises yet another question: If the ALCM only serves a “back-up” role in the current U.S. nuclear war plan, how is it wise to invest $20 to $30 billion in a completely new system?

Meanwhile, the Air Force is significantly increasing the lethality of its conventionally armed cruise missiles.

For example, the service is purchasing thousands of stealthy precision air-to-surface standoff cruise missiles designed to attack targets from outside the range of adversary air defenses. Known as the JASSM-ER, the missile will have a range of roughly 500 miles and be integrated onto the B-1, B-52, B-2, F-15E, and F-16 aircraft — and likely on the F-35 and B-21 as well. The Air Force is also planning to arm the JASSM-ER with a new computer-killing electronic attack payload. The technology is designed to have an effect similar to an electromagnetic pulse. The Navy’s sea-launched Tomahawk cruise missile is also a highly capable and continually improving conventional standoff weapon, and it has an even longer range than the JASSM-ER.

Enhanced warfighting capabilities

Given there is nothing unique about the penetrating mission of a nuclear ALCM, devotees of the missile often emphasize other supposed attributes of the system, including that it would come in handy in potential scenarios involving limited nuclear escalation.

The idea here is that the weapon system, by virtue of the lower yield of the nuclear warhead it carries, provides the president with the ability to respond proportionally to a smaller-scale nuclear attack by an adversary, thereby enhancing the U.S. ability to deter such attacks from taking place and assuring allies that Washington will respond decisively to limited use.

Yet U.S. nuclear capabilities would remain highly credible and flexible even without a nuclear ALCM. The arsenal includes other weapons that can produce more “limited” effects, most notably the B61 gravity bomb. More importantly, the notion the use of nuclear weapons can be fine-tuned to carefully control escalation to a full-scale nuclear exchange is very dangerous thinking. It is highly unlikely that an adversary on the receiving end of a U.S. nuclear strike would (or could) distinguish between a large warhead and a small warhead. The fog of war is thick. The fog of nuclear war would be even thicker.

Large or small, nuclear weapons are extremely blunt instruments, both in terms of their destructive power and the taboo associated with the fact they have not been used in 70 years. As Michael Krepon has elegantly put it, the case for the LRSO “demands a fealty to nuclear warfighting concepts that most Americans will be hard-pressed to understand. The nuclear deterrence business is most persuasive to taxpayers in the abstract; particulars require the suspension of disbelief.”

Other arguments in favor of the LRSO are also unconvincing. The Defense and State Departments claim that strategic bombers armed with ALCMs and gravity bombs are more “stabilizing” than the capabilities inherent in the other legs of the triad because the airborne leg provides a nuclear response option that is observable and does not pose the threat of a disarming surprise attack. Yet a B-21 bomber armed with the LRSO will be more difficult to detect than the current B-52/AGM-86B arrangement, and may not always be observable or provide more potential for warning, especially in a crisis. Indeed, some supporters of the LRSO emphasize its utility for achieving tactical surprise in combat.

The LRSO raises serious questions about stability that have yet to be fully explored. The new missile and its associated refurbished warhead could be vastly more capable than the current ALCM in terms of characteristics such as stealth, speed, range, accuracy, and yield variability. As noted above, the missiles will be deployed on the more advanced B-2 and B-21 bombers. In addition, some sources have said that the Pentagon is envisioning potential uses for the new cruise missile that go beyond “the original mission space” of the ALCM, namely in contingencies involving China.

Furthermore, as highlighted by William Perry, President Bill Clinton’s defense secretary, and Andrew Weber, President Barack Obama’s assistant secretary of defense for nuclear, “cruise missiles are a uniquely destabilizing type of weapon” due to the fact that “they can be launched without warning and come in both nuclear and conventional variants.”

The possible risk of miscalculation and unintended escalation posed by the LRSO requires far more scrutiny than the blithe assertions from the administration that the missile will be stabilizing.

Indefensible Costs

The case for the LRSO is further undermined when one considers the high budgetary costs and significant opportunity costs. The United States is planning to rebuild all three legs of the nuclear triad and their associated warheads at a cost and on a schedule that many military leaders say is unsustainable. As Todd Harrison, the director of defense budget analysis at the Center for Strategic and International Studies, convincingly demonstrates in a recent report, the cost to sustain the nuclear mission is scheduled to peak during the 2020s and overlap with heightened levels of projected spending on conventional weapon system modernization programs.

While no one knows for sure what the military budget will look like after the expiration of the Budget Control Act in 2021, it seems unlikely that there will be enough money to fund all of the military’s nuclear and conventional modernization proposals. This will force the U.S. government to choose between the nuclear effort and other military priorities. What’s more, the president and his military advisors have determined that the United States can reduce the size of its deployed strategic nuclear arsenal by up to one-third below the 2010 New Strategic Arms Reduction Treaty (New START) levels, Nonetheless, the proposed nuclear spending plans are based on maintaining the New START levels in perpetuity.

The bloated U.S. nuclear arsenal of approximately 4,700 weapons is largely irrelevant to the most pressing national security challenges the United States faces. Retaining an unnecessarily large arsenal and enhancing U.S. nuclear warfighting capabilities will not help Washington address the challenges posed by great powers such as Russia and China. If anything, doing so will exacerbate relations with these countries.

The choice is clear: chart a more realistic path for the nuclear arsenal that doesn’t severely constrain the force-sizing options of future presidents and reduces the risk of doing serious damage to conventional capabilities and other national security programs. As an early step in this course correction, the Pentagon should cancel its new cruise missile program and prioritize continued investments in the other legs of the nuclear triad and more relevant and usable non-nuclear capabilities, including longer-range conventional cruise missiles.

Doing so would be far more beneficial to U.S. security than spending billions to buy a redundant new nuclear missile unneeded for either deterrence or assurance.


Kingston Reif is the Director for Disarmament and Threat Reduction Policy at the Arms Control Association. You can follow him on Twitter at @KingstonAReif.


Image: USAF, Senior Airman Benjamin Gonsier