How the new nuclear-armed cruise missile might aid disarmament

The idea of banning nuclear armed cruise missiles is gaining traction, most notably through its promotion by former Secretary of Defense William Perry, the driving force behind the US’s current nuclear-armed cruise missile when it was birthed in the 1970’s and 80’s. Although the cruise missile is but a cog in the US nuclear and conventional arsenal, it is an increasingly important one, and indeed a cog that will cost the US taxpayer billions of dollars if the Air Force gets its way and fields a new nuclear armed cruise missile—the Long Range Stand Off Weapon, or LRSO.

Thus far, the arguments for and against this new weapon have been largely partisan, either calling for complete unilateral disarmament or defending it without a blink of an eye. Partisan rhetoric aside, the likelihood is that this weapon, along with its modernized W80 nuclear warhead, will be fielded in the 2020s. So it is now prudent—if perhaps counterintuitive—to suggest how this weapon can be used to further nuclear disarmament.

Why all the cruise missile fuss now? Cruise missiles armed with nuclear warheads have been deployed for many years by the United States, the Soviet Union, and now Russia. Some have been subject to control by the Intermediate Nuclear Forces Treaty (INF) and some by President George H.W. Bush’s Presidential Nuclear Initiatives. In the United States, this has resulted in them being deployed only on the Air Force’s B-52H strategic bomber. These remaining nuclear cruise missiles are limited loosely under the current bilateral nuclear arms control treaty between the United States and Russia, New START. The Air Force is developing a new nuclear armed air-launched cruise missile (ALCM) to replace its aging AGM-86B nuclear armed cruise missile, which is coming near to the end of its life span.

Because budget requests are ongoing, there has been movement to promote a nuclear cruise missile ban as politicians deliberate funding. Also bringing this issue into the limelight is Russia's use of its own cruise missiles against targets in Syria over the last year, launching them from strategic bombers, surface ships, and submarines. Their effectiveness has been noted and their technical parity with US weapon systems is in little doubt. Russian President Putin has stated that the missiles, which have carried conventional arms in Syria, can also be armed with nuclear warheads.

All of these circumstances have prompted different responses to the question of whether the United States should continue to field nuclear cruise missiles by allocating budget for the new LRSO, or ban them unilaterally, with the hope that others, such as Russia and China, follow suit.

The argument behind Perry’s call to President Obama to unilaterally ban nuclear armed cruise missiles focuses on their destabilizing nature, comprised of two primary factors: nuclear ambiguity and a lowered threshold for use. The LRSO is designed to deliver either a nuclear or a conventional warhead. If an opposing force detects an LRSO launch, then, it will not know if it is under conventional or nuclear attack—until detonation. This ambiguity might provoke the opposing force to mistakenly escalate from conventional warfare to nuclear. At the same time, nuclear cruise missiles are designed to deliver small-yield warheads against smaller targets in a limited nuclear war that, theoretically at least, does not lead to the use of large-yield weapons and global, mutually assured destruction. This limited strategy promotes the legitimacy of the use of nuclear weapons and, in Perry’s view, blurs the line between conventional and nuclear warheads.  

The argument in favor of the LRSO follows these approximate lines: The US already deploys strategic bombers with nuclear-armed cruise missiles. While the LRSO would be a modernized version of the current missile, it is not a new tactic or weapon type. The United States also currently deploys another type of conventionally armed cruise missile (the Joint Air to Surface Standoff Missile or JASSM) from the same strategic bomber. Therefore, a cruise missile modernization program is not destabilizing because the possibility of blurring the lines already exists and will continue to exist as the LRSO and the JASSM will be deployed on all of the US’s strategic bombers. Also, the cruise missile is increasingly important because it is the only weapon that can effectively target much of the Russian and Chinese nuclear arsenal. Both countries are mobilizing their ground-based ballistic missiles on trucks and trains. These cannot be effectively targeted with the United States' ground- and submarine-based ballistic nuclear missiles, nor can they be effectively targeted with strategic bombers armed with gravity bombs. So cruise missiles are required to hold Russian and Chinese strategic forces at risk and maintain the relative nuclear stability we have become accustomed to.

And finally, the ability of US strategic bombers to penetrate contested air space is not guaranteed. Although the future B-21 bomber will utilize stealth technology, it is not known how long it will stay ahead of the opposition’s air defense capabilities. Therefore, a weapon is required that can be fired outside of enemy air defenses to either destroy those defenses to allow the bomber through, or indeed to strike other targets. This is the so called standoff capability.

Holes in the arguments. Unfortunately, both of these positions lack in detail, and it is the detail that brings clarity to this issue.

First of all, the issue of ambiguity—whether a missile is carrying a nuclear or conventional warhead—is actually carried over from ballistic missiles. Some states, such as China, have opted to field ballistic missiles that can be armed with either conventional or nuclear warheads—so called dual-capable missiles. Because the launch of ballistic missiles can be relatively easily detected, there is a real issue for someone deciding how to respond; he cannot know if his country is under nuclear or conventional attack.

The same cannot be said about cruise missiles. Because of the nature of the cruise missile, its launch is extremely difficult to detect: Heat signatures are so small they cannot be detected by launch detection satellites used for ballistic missiles, launch areas can be planned to fall outside of radar coverage, and jamming techniques can also be utilized. As a result of the small radar signature of the missile and its low-level flight paths, which route around known defenses, an opposing force is not likely to know anything about incoming cruise missiles until they reach their targets, whether they are fired from stealthy or non-stealthy bombers. Effective cruise missile defense has not been realized, exactly because these missiles are extremely difficult to detect.

Second: Offering the president the opportunity to use cruise missiles in a limited nuclear war is not necessarily a lowering of the nuclear threshold. Although these weapons might provide the means for a president to use nuclear weapons, that doesn’t necessarily mean his or her threshold for using them will lower.

Third, the ability to target ground mobile Russian and Chinese nuclear forces with cruise missiles relies on increased missile accuracy and the ability to hit moving targets. It does not necessarily rely on the use of nuclear warheads, a point that the Russian’s themselves have raised. The current conventionally armed cruise missile, the Joint Air to Surface Standoff Missile (JASSM), is already able to complete this mission. So why is there a need for the LRSO?

Fourth, it is not unreasonable to see a need for a standoff weapon. The ability of the B-2, the United States' existing strategic stealth bomber, to penetrate contested airspace is uncertain, and technical advances in detection methods will probably greatly reduce the stealthiness of its successor, the B-21, within its service life, leaving the US without a strategic bomber if it is not equipped with a standoff weapon. The B-2 fleet is small, and it is quite likely that, because of cost, fewer B-21s will be built than currently forecast. A standoff weapon would ensure the usability of the new bomber, but this standoff weapon does not have to be nuclear armed. If the LRSO does not have a unique capability compared to JASSM, why is there a need for the new standoff weapon?

How the LRSO can be used to further nuclear disarmament. The LRSO is not a nuclear weapon. Instead, it is a dual-capable weapon platform, meaning that roughly half of the 1,000 or so missiles that will be built will likely be fitted with a nuclear warhead and the other half with a conventional warhead. There are 528 W80 nuclear warheads being modernized for deployment on the LRSO. And although the current nuclear-armed cruise missile was originally capable of delivering nuclear and conventional warheads, it is currently used only for the nuclear mission. This means that the Air Force is replacing a nuclear cruise missile with a dual-purpose cruise missile.

Upon deployment of the LRSO, the United States and Russia would each have cruise missiles capable of carrying both nuclear and conventional warheads. Both sides would then be able to approach the negotiation table with equal capability, translating into an arms control opportunity: Each side could retire the nuclear warheads on its cruise missiles without retiring the missiles themselves.

It has long been said that nuclear weapons will remain the ultimate symbol of power only until conventional weapons can produce the same result. The LRSO could be a real instance of a conventional weapon taking on the role of a nuclear weapon. Because of technological progress, the conventionally armed air-launched cruise missile can do the job of a nuclear-armed ALCM. The LRSO might be the route to realizing this change.

Stability needs to be maintained on the path to disarmament. While unsavory, the doctrine of mutually assured destruction is the foundation of  bilateral stability; to maintain stability, the United States must have means to hold Russian nuclear weapons at risk, and vice versa. The LRSO could allow both sides to negotiate from an even standing; if negotiations to destroy cruise-missile nuclear warheads were successful, the LRSO could be the last nuclear-armed cruise missile of any kind fielded by the United States.

The argument for a nuclear armed cruise missile is not persuasive because a conventionally armed cruise missile can now perform the missions that the nuclear variant is expected to carry out. Indeed, the argument for why the LRSO would out perform the JASSM has been missing from public debate. It is probably too late in the approval process to ask why the LRSO needs to exist. But the new cruise missile does offer new opportunity to further nuclear disarmament, in two ways: First, its political weight is huge. It offers the United States a place of strength at the negotiating table; the nuclear capability of the LRSO is a huge chip to trade in arms-reduction talks. Second, the LRSO will also promote the transition of some nuclear weapon platforms to conventional use, a process that, if generalized, could reduce the risk of nuclear warfare. This arms control opportunity is what can be salvaged from an otherwise unwarranted modernization of a nuclear weapons platform.