Wargaming and Deterrence Options: Signalling a Low-Yield Response

When wargaming a Russian attack on the Baltic states, the Rand Corporation, demonstrated that current NATO forces in Europe are an insufficient deterrent. Findings indicated that if Russia was to attack the Baltic states of Estonia and Latvia, the longest length of time it would take their forces to reach the outskirts of Tallinn and Riga is 60 hours. RAND found that a NATO force of about seven brigades, including three heavy armored brigades supported by air power and adequate land-based fire support would be necessary to prevent a rapid defeat until more forces can arrive in Europe. This, they argued would be the necessary conventional force required to deter a Russian attack.

The destruction of NATO would mean a great victory for Putin who views the alliance as a major threat to Russian national security. So, what can realistically be done to deter Russia from one day taking this gamble? The answer is twofold. Appropriate nuclear signaling in combination with appropriate non-strategic nuclear capabilities.

Let’s look at capabilities first. The current non-strategic nuclear structure of B-61 gravity bombs based in Europe is incapable of adequately deterring a Russian attack. The countering of any mistaken perception of an exploitable gap in regional deterrence was emphasized in the 2018 U.S. Nuclear Posture Review and formed the basis for the proposal to add low-yield SLBMs and SLCMs into the arsenal. The shortcoming of the B-61 is that it has very limited capability due to the need to penetrate modern air-defenses such as the long-range S-400 and medium-range Buk M2 missile systems, not to mention the up and coming S-500.

The key to using non-strategic nuclear weapons to deter a Russian attack is having a credible plan of action should deterrence fail. If Russia launched a full-scale invasion of the Baltic States and reached the outskirts of Tallinn and Riga, how would the weapons be used? With the current option being B-61s, the F-16 and PA-200 aircraft would need to first have the required combat range to reach their target and then successfully evade Russian air-defenses. With their current basing locations, the aircraft carrying the B-61s do not even have the range to encompass the total territory of Estonia and Latvia, let alone over the border into Russia, aside from Kaliningrad. They also lack the capability of evading modern Russian air-defense missile systems. This presents a significant problem, as deterrence is relying on options that an enemy may perceive as impotent.

This is where the addition of low-yield SLBMs and SLCMs will close the gap and add a credible non-strategic deterrent. During the Cold War, NATO deployed a range of tactical options including nuclear artillery and mines to use against a conventionally superior Soviet-led force in the event that it invaded Western Germany. The problem is evident in this scenario, as it involved the potential use of multiple nuclear weapons on allied territory. The new additions solve this problem, as they could be used behind enemy lines in Russia itself, in the event of an invasion against NATO, to destroy airfields, logistical centers, military bases, air-defenses and columns of armored forces ready to deploy to the front.     

The SLBMs proposed to be deployed before the SLCMs, would use a modified W76-1 warhead with an ideal variable yield of 0-10kT, as opposed to the current 100kT warhead. The delivery platform would be the Trident II D-5 missile, launched from the Ohio Class ballistic missile submarine. With its intercontinental range, speed and accuracy, this low-yield option would be able to penetrate Russian airspace and destroy targets specifically involved in supporting military action at the front. While they may not destroy the spearhead itself, the troops that have already pushed into the Baltics, they would snap the spear, preventing further adequate reinforcement and eliminating or dampening Russian Anti-Access Area Denial (A2/AD) capabilities.

Next, we move to the so-called “discrimination problem,” posited by academics such as Vipin Narang. This is where appropriate nuclear signaling comes into play. The “discrimination problem” concept refers to Russia potentially mistaking an incoming low-yield SLBM for a full-scale disarming first strike. Russia cannot predict the yield of the incoming missile before it detonates. Thus it could be 0-10kT or 488kT, in the case of a W88 warhead, also fitted to the Trident II D-5 SLBM. The fear illustrated by this problem is that Russia reacts to the incoming missile by launching a full-scale retaliatory nuclear strike against the continental United States to prevent their own ICBMs from being destroyed in their silos.

 This “discrimination problem” is a concern to be addressed but can be circumvented by appropriate signaling. The U.S. must be on the front foot in deterring a Russian invasion of the Baltic states by specifically and publicly declaring that a Russian military advance against NATO may be met with a non-strategic nuclear attack on its territory to halt the advance. This appropriate signaling will make clear to Putin and Russian military planners that the U.S. is serious about defending NATO and has the nuclear means to do so, without resorting to a full-scale strategic nuclear attack resulting in a global nuclear exchange.

In spite of the argument proposed by Narang, it is unlikely that Russia would mistake one or two incoming SLBMs for a strategic first strike even with MIRV capabilities. Russia has an estimated 318 ICBMs in fixed silos and on mobile launchers, not to mention its sea and air-based deterrent. To launch a full-scale retaliatory strike based on one or two incoming SLBMs is an unrealistic concept.  

While some academics and abolitionists may decry the idea of threatening limited nuclear use in response to a Russian invasion of NATO and argue that it makes a nuclear exchange more likely, in fact, the opposite is true. A deliverable and penetrable low-yield nuclear option coupled with specific and straight-forward signaling of intentions removes uncertainty and provides an option short of global nuclear war. As it stands, Russia may make the miscalculation due to an inadequate NATO deterrence posture and mixed messages from the current U.S. administration that the gamble may pay off. The attractive lure of successfully dismantling the NATO alliance through an invasion of the Baltic states must be completely taken off the table with adequate capabilities and appropriate signaling. Better to take steps to deter now, rather than scramble to push back a Russian force dug into Baltic territory.              

Adam Cabot has a Masters in International Relations and is currently researching Russian nuclear strategy.