The US deployment of low-yield nuclear warheads is a response to both Russian and Chinese strategies.
The US administration is strengthening nuclear deterrence with new delivery systems aimed at eroding the confidence of Washington’s adversaries in their own capabilities.
– The US has recently deployed low-yield nuclear warheads onboard submarines
– The new deployment is designed to bolster extended deterrence after the 2018 Nuclear Posture Review and US withdrawal from the INF treaty in August 2019
– Experts contend that deployment of these tactical weapons lowers the threshold for use
– Washington has stated its desire to engage in strategic dialogue with both Moscow and Beijing
THE US EXPANDS ITS NUCLEAR OPTIONS
The US has supplemented its existing deterrence capabilities with the recent deployment of low-yield W76-2 submarine-launched ballistic missile (SLBM) nuclear warheads onboard Ohio-class submarines. This is significant because SLBMs provide a more survivable delivery system in the event of conflict as submarines are more difficult to detect and destroy than other delivery systems like aircraft.
The new deployment, announced by Undersecretary of Defence for Policy John Rood, is intended to signal to Washington’s adversaries that an attack against a US ally will be met with force. This has drawn criticism from nuclear experts wary of the danger of these weapons and the potential lowering of the bar for nuclear conflict. It has also come at a time when the US Army is reestablishing its command in Europe to counter Russia, tensions between the US and Iran are high, Taiwan looks to be moving away from an ever more assertive Beijing, and Washington has been criticised for suddenly abandoning Kurdish allies in northern Syria.
WASHINGTON’S NUCLEAR POSTURING
The deployment is primarily a result of the February 2018 Nuclear Posture Review conducted under the tenure of former defense secretary James Mattis. The review identified a ‘perception gap’ in deterrence capabilities, noting that Moscow believed it had a comparative advantage over the US when it came to smaller mid-range nuclear weapons systems. It also concluded that this belief could give Moscow the confidence to use these weapons in more localised conflicts without risking mutually assured destruction (MAD). The deployment of the W76-2 is seemingly a part of Washington’s plan to narrow that perception gap and erode Moscow’s confidence in its own capabilities.
The Nuclear Posture Review is also linked to the US withdrawal from the Intermediate-Range Nuclear Forces Treaty, announced in October 2018. The actual withdrawal in August 2019 was justified on the grounds that Russia had broken the terms of the agreement. One breach, cited in a Congressional Research Service report, came in the form of new ground-launched, short-range ballistic missile platforms like the one displayed by the Russian military in May 2019. This launcher carried four cruise missiles capable of hitting targets over 500 km away — a range prohibited by the treaty. However, Russia blamed the US for the termination of the treaty, which was ultimately outdated and no longer reflected the realities of the current security environment.
Even though the announcement of the W76-2 deployment was aimed explicitly at Moscow, the Nuclear Posture Review also labelled China as increasingly aggressive and therefore threatening. The review highlighted the greater salience of nuclear forces in both Russian and Chinese strategies when compared to the self-professed US efforts to reduce its nuclear arsenal and the prevalence of nuclear weapons.
The deteriorating threat environment described in the review has continued to decay. Neither China nor Russia have changed their strategic posture and Washington has suffered a significant reduction of both prestige and credibility as global security guarantor and leader of the liberal international order. In light of this, the deployment of the W76-2 capability aims not only deter Moscow from using a smaller nuclear weapon against NATO but to reverse some of the declining perceptions of US power and credibility.
HAS THE BAR BEEN LOWERED FOR A LIMITED NUCLEAR WAR?
The stated aim of the deployment of the W76-2 is to deter Russia from using its own low-yield nuclear weapons against the US and its allies. However, the addition of another delivery system also has the potential to lower the threshold for use in both first and second strike scenarios (a.k.a. preemptive and retaliatory scenarios). Despite this, the first use of nuclear weapons by the US remains highly unlikely considering the political fallout and international outrage that would follow. But if the US or one of its allies were to come under nuclear attack, a proportionate second-strike is made more likely by the deployment of this delivery system. Not only could the US respond proportionately, but the more survivable SLBMs increase the chances of the US retaining that second-strike capacity during a conflict.
These new low-yield weapons also have the potential to act as a deterrent to Iran, North Korea and even China. One issue faced by US policymakers has been these states are geographically close to US allies. Having the option to use low yield nuclear weapons against these states bolsters deterrence, as US allies are less likely to be adversely affected than a scenario in which high-yield or strategic weapons are used.
The supplemental nuclear capability is designed to complicate the decision making of Washington’s adversaries when it comes to the use of their own nuclear weapons, and may be a part of a wider strategy to bring both Russia and China to the table when the New START treaty — which limits the number of nuclear warheads the US and Russia can deploy — expires in 2021. The Nuclear Posture Review explicitly states that the US seeks the same dialogue with China as it has previously held with Russia and it is hard to imagine a meaningful arms control agreement between only two of these three states. Additionally, whilst Russia retains an extensive nuclear arsenal, the Russian economy is unlikely to be able to sustain a Cold-War style arms race against the US and China.
The assumption that Russia will fall behind in an arms race won’t only scare Moscow. Both Washington and Beijing would recognise the importance of an arms control agreement that allowed Moscow to maintain effective deterrence even as its capabilities lagged behind those of the US. This will be essential because, in a MAD world, a state that loses confidence in its capacity to threaten its adversaries is perhaps more dangerous than one that feels overconfident.