The US has just tested a new type of nuclear-tipped air launch cruise missile, reaffirming the viability of the air-based leg of its nuclear triad against evolving threats from near-peer adversaries China and Russia with profound implications for regional stability and global non-proliferation norms.
This month, The Warzone reported that the US Air Force had conducted nine flight tests of its future nuclear-tipped AGM-181A Long Range Stand Off (LRSO) cruise missile prototypes, including one test with a mock nuclear warhead.
The Warzone notes that the milestones were reported in a 2022 Selected Acquisition Report (SAR) released last month, with the tests aiming to gauge the missile’s stealthy capabilities.
The report mentions the US Air Force has selected Raytheon to develop the AGM-181A LRSO missile, which will replace the AGM-86B Air-Launched Cruise Missile (ALCM). The missile is part of the Long Range Strike family and has reportedly undergone nine successful major flight tests, demonstrating its high survivability with a stealthy airframe.
The Warzone says the Pentagon’s 2022 acquisition report classified all nine test events as flight tests, but not all involved independent missile flights. It notes that captive carry sorties were conducted for safety and that four powered-flight tests were deemed successful, including a Controlled Test Mission (CTM-1) test demonstrating the design’s maturity, manufacturing processes and navigation system performance.
The Warzone report also says that the US Department of Energy’s National Nuclear Security Administration (NNSA) has revealed that the first powered flight test of an AGM-181A LRSO Cruise Missile with a W80-4 nuclear warhead launched from a B-52 bomber was conducted, with a decision about low-rate initial production expected in 2027.
The AGM-181A LRSO with the variable yield W80-4 warhead may be crucial for the US to fill a perceived nuclear deterrence gap resulting from the downsizing of its nuclear arsenal after the previous Cold War while its near-peer adversaries, China and Russia, continued to develop tactical nuclear weapons.
In a January 2021 article for The Heritage Foundation, Patty-Jane Geller mentions that the US AGM-86B ALCM has been upgraded to be operational until 2030, 38 years beyond its intended lifetime.
Geller notes that Russia and China’s improving air defense systems make penetrating hostile airspace increasingly prohibitive and that continuing to use the AGM-86B instead of developing the AGM-181A LRSO would send a signal to adversaries that the US lacks a modern and capable air-launched nuclear cruise missile capability.
Geller also notes that the US Air Force must maintain a credible air-based nuclear deterrent, mentioning that with the AGM-86B ALCM retiring soon, the AGM-181A LRSO is the only solution to keep the B-52H nuclear-capable.
She also says that while the US Air Force has committed to ordering at least 100 B-21 Raiders to replace B-2 and B-1 bombers, only a stealthy cruise missile such as the AGM-181A LRSO can hold specific targets at risk. In addition, she says that the LRSO will ensure the B-21’s stealth technology remains effective against evolving military technology and advanced air defenses.
Geller also mentions that the AGM-181A LRSO program allows bombers to train on multiple targets while standing off from enemy air defenses, thereby contributing to the credibility of US deterrence.
Such capability, Geller notes, allows the US president to deter an adversary from attacking first and respond proportionately to an adversary’s limited use of nuclear weapons. That flexibility, she says, makes air defense more complicated for US adversaries, forcing them to plan for incoming cruise missiles from multiple attack vectors.
Moreover, Geller says that the AGM-181A LRSO reduces risk to bombers and personnel, thus increasing the credibility of deterrence as adversaries will be less convinced of US willingness to send people flying into air defenses than if the US can launch safely from friendly territory.
The development of the AGM-181A LRSO may spark a proportionate nuclear response from China and Russia, which could entail strategic-level cooperation to increase their respective nuclear arsenals, sparking a renewed nuclear arms race with the US.
In March 2023, Asia Times reported that Russia plans to provide China with fast breeder nuclear reactor technology, allowing Beijing to significantly grow its nuclear arsenal and tip the global nuclear bomb balance.
An agreement was announced by Chinese President Xi Jinping and Russian President Vladimir Putin to continue the development of fast breeder nuclear reactors that are specifically designed for the production of plutonium, which can be used in nuclear weapons.
In December 2022, Russia’s Rosatom transferred 25 tons of highly enriched uranium to China’s CFR-600 nuclear reactor. US officials and military planners believe the reactor will help China increase its nuclear arsenal from 400 warheads to 1,500 by 2035.
However, China denies this and claims the reactor is part of its civilian power grid and will be installed toward the aim of becoming the world’s top nuclear energy generator.
Russia has shifted its approach towards China due to the Western sanctions imposed after its military invasion of Ukraine. Despite long-term concerns about China’s potential threat in Russia’s Far East, Moscow has provided it with nuclear technology to strengthen its position vis-a-vis the West.
China is growing its nuclear arsenal to improve the likelihood that its arsenal will survive in the event of a war with the US. China can strengthen its second-strike capability by having a more extensive and more varied nuclear arsenal. This project puts China in a better position to use its nuclear weapons as a coercive tool and employ them if necessary.
America’s development of the AGM-181A LRSO also has profound implications for regional military strategies and strategic-level deterrence.
For one, the AGM-181A LRSO missile could be crucial in deterring or responding to aggressive actions in the Taiwan Strait, where China has been conducting military exercises and missile tests. The presence of a stealthy, long-range missile like the AGM-181A LRSO could discourage such drills and tests. Moreover, the AGM-181A LRSO’s ability to penetrate advanced missile defenses would be critical in a conflict.
In the South China Sea, tensions are also running high due to territorial disputes and China’s recent militarization of artificial islands. The AGM-181A LRSO could serve as a deterrent in this theater as well. The 181A LRSO’s long range could allow it to strike from distances beyond the reach of enemy defenses, which could help maintain freedom of navigation in the contested waters.
The AGM-181A’s development could also have profound implications for global nuclear non-proliferation by contradicting the spirit, objectives and disarmament provisions of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).
While the AGM-181A LRSO per se is not a nuclear weapon, its development as a nuclear delivery system could also raise concerns about potential violations of the Comprehensive Nuclear Test Ban Treaty (CTBT).
Additionally, amid ongoing nuclear arsenal modernization programs and uncertain statuses of other key treaties like New START, the AGM-181A LRSO’s development could further complicate and dangerously jeopardize diplomatic efforts between nuclear-armed states amid rising tensions in what some see as a budding new cold war.