Rodger Baker charts the direction that global nuclear deterrence might take as a consequence of Russia’s invasion of Ukraine
There has been much talk lately about the impact of Russia’s latest invasion of Ukraine on global nuclear deterrence. The short answer is that the war in Ukraine highlights both the continued effectiveness and the limitations of nuclear deterrence. The more significant emerging challenge is not the longstanding nuclear balance between the United States and Russia, but the trilateral nuclear dynamic driven by China’s expanding nuclear arsenal and evolving nuclear doctrine.
In many ways, the war in Ukraine has reinforced the basic tenets of nuclear deterrence. During the Cold War, the risk of nuclear conflict helped stay the hands of the Soviets and Americans. Proxy wars were common, but direct confrontation between the superpowers was curtailed. In the current case, Russia has kept the kinetic war contained to Ukraine, and the United States has refrained from direct military involvement in Ukraine. The ever-present risk of broader nuclear war constrains – or ‘deters’ – certain actions by each side. Russia considers any NATO supplies fair game once they cross the Ukrainian border, but Moscow refrains from striking inside Poland to disrupt supplies to Ukraine.
Washington is steadily expanding what it offers Ukrainian forces, from material to tactical targeting intelligence. But the United States is not providing a no-fly zone, nor is it actively engaged in military operations on the ground in Ukraine. For both Washington and Moscow, the risk of direct confrontation and its potential for escalation to nuclear war serves as a check on options and actions.
At the same time, nuclear deterrence is not blanket deterrence. It targets specific actions or behaviours. The US nuclear arsenal did not stop Russia from invading Ukraine, nor has it given Washington leverage to convince Moscow to withdraw. That is because neither action falls within the communicated realm of nuclear deterrence. Viable deterrence requires three things: demonstrable and robust capabilities, a willingness to use the deterrent assets, and clearly communicated ‘redlines’ or proscribed actions.
The possessor of the deterrent capability must both decide and then clearly articulate what actions of the opponent would trigger a resort to the deterrent, as opposed to other political, military or economic tools. There is some small room for ambiguity, but not much when it comes to the potential for rapid nuclear escalation. As Dr Strangelove taught us, ‘the whole point of a Doomsday machine is lost, if you keep it a secret!’
A nuclear deterrent, then, doesn’t guarantee peace, nor does it coerce the opponent to shift political views. Instead, it sets limits on behaviour. Not all actions rise to the level of nuclear deterrence, particularly when states have other tools in their strategic toolboxes. Nuclear weapons are often retained for ‘existential’ threats, or challenges to the survivability or territorial integrity of the nation.
In the case of Ukraine, this is why the United States and its European partners are on high nuclear alert: Russia has asserted that Ukraine is an existential and territorial issue. This doesn’t mean Russia is ready to use nuclear weapons in Ukraine, but rather that Moscow has signalled that there are limits to acceptable Western assistance to Kyiv.
It is up to the West to interpret Russia’s intent and willingness, to discern whether Moscow is serious, or is bluffing. More often than not, when it comes to nuclear weapons or other weapons of mass destruction, the prudent course is to err on the side of caution. In North Korea, for example, the United States adjusted its assessments and policies based on the assumption of North Korean nuclear capability even before it was fully proved. A faulty assumption in the opposite direction would have disastrous consequences, for example, had the United States tried to militarily pre-empt the North’s nuclear development, only to be met with an active nuclear capability.
Within its limits, then, nuclear deterrence is still holding in the Ukraine crisis. Both sides are constraining their actions, despite clear errors and setbacks on the Russian side and strong political pressure on the US and NATO side. But it is not only nuclear deterrence that shapes the willingness and actions of the different sides. As a key component of strategic deterrence, nuclear deterrence sits as the base of broader deterrent and response capabilities.
Russia doesn’t refrain from attacking staging areas inside Poland just because it fears a US nuclear strike on Moscow. A vast conventional arsenal would come to bear in an escalating conflict between Russia and NATO. But even the idea that the warfare remains in the conventional realm is predicated on the underlying nuclear capabilities – capabilities that quickly shift war from some distant fight to something very real and deadly to the core leadership of a country. Nuclear weapons’ reach and devastating power provide them with both their deterrence power and constrain their employment.
Most nuclear doctrine, however, is based on bilateral assessments, particularly that between the United States and Russia (née the Soviet Union). Peer nuclear warfare has evolved its own set of deterrence ‘rules’ and norms. Throughout the Cold War the two superpowers may have fought numerous proxy wars, but the ‘big one’ never occurred – and that can be attributed in no small extent to the effectiveness of nuclear deterrence by both sides. But that bilateral balance is fracturing. Small nuclear powers like North Korea, Israel or even potentially Iran do not fundamentally challenge US nuclear deterrence – they simply cannot outgun the United States. But China’s rapidly expanding and modernising nuclear arsenal and its evolving nuclear doctrine create a new challenge for US nuclear deterrence strategy.
Actions taken to manage one nuclear peer may have an alternate effect on the other. Part of the logic behind the US withdrawal from the Intermediate-Range Nuclear Forces Treaty, for example, was the value of intermediate-range nuclear missiles in the Indo-Pacific theatre. A management tool in one theatre – INF in Europe – constrained US options in another, the Indo-Pacific. US nuclear modernisation to deal with the rapidly changing China dynamic is also likely to trigger counteractions by Russia.
Even moves to manage tertiary nuclear powers can have unintended consequences in the broader strategic nuclear balance. The deployment of Terminal High-Altitude Area Defence missile defence systems to South Korea reinvigorated China’s drive for more mobile and dispersed missiles, and raised concerns in Russia about its Pacific front. A three-way nuclear race leaves little room for new agreements or arms control measures, and requires the United States to think not only in terms of two bilateral nuclear balances, but also to consider the potential for coordination or cooperation between Moscow and Beijing in times of crisis.
The current conflict in Ukraine has reinforced to smaller nuclear powers the importance of maintaining their nuclear capabilities and demonstrating their deterrence is real and robust. This crisis may reinvigorate the push by countries that have sought nuclear weapons but not attained them to finalise their nuclear deterrent. For other small and middle powers, the message of Ukraine is that without an express treaty, one nuclear power is unlikely to defend you against another. You either need to climb under someone’s nuclear umbrella, find another way to strengthen your conventional deterrence – or use unconventional means through cyber activities. And for the big nuclear powers, Ukraine reinforces the complexity of a multipolar world, one where nuclear deterrence may dissuade direct confrontation between the big powers, but at the same time increases the likelihood of conventional military actions around their periphery.
Rodger Baker is Senior VP of Strategic Analysis, Stratfor