The Ukraine war shows the theory of nuclear deterrence needs a relook

A mushroom cloud rises moments after the second atomic bomb was dropped on Japan by the US. This time the target was Nagasaki and more than 73,000 were killed. AP Photo

A letter from then UK prime minister Margaret Thatcher to then USSR leader Mikhail Gorbachev in 1985, as the Soviet Union was entering the endgame of decline and fall, carefully outlined London's recognition that Moscow had as much right to feel secure as its western counterparts.

Tony Brenton, a former UK ambassador to Moscow, cited that missive last week as he surveyed the stakes in the Ukraine-Russia war. The ambassador's reference point of an overarching balance of interests that is decades in the making was dramatically underlined when fighting broke out around Ukraine's Zaporizhzhia nuclear energy facilities. As a fire raged around the facility, a 1980s-style scare went around the world on the possibility of a nuclear incident with far-reaching consequences.

A year after the Thatcher letter, the explosion at Ukraine’s Chernobyl plant took place. More than 35 years later, western leaders warned last week that the safety of all of Europe was directly threatened by events at a nuclear facility in that country.

Under international law, civil nuclear power plants and the peaceful development of nuclear technologies are distinct pillars from developing nuclear weapons. Nevertheless, a war involving a nuclear power has revived for many the spectre that the ultimate weapon would be used.

Escalations open the perils of miscalculation, misperception and misjudgement

TikTok is reportedly awash with videos on what to do if armageddon hoves into view. For some, it feels as if the library of Cold War information films on the “four-minute warning” should be given a modern spin. Mr Brenton noted there was an entire body of literature written during the Cold War on dealing with an actor who was not making straightforward calculations. In the first instance, nuclear weapons assume prominence earlier in the crisis than negotiators would assume.

Nuclear deterrence is built on, but not exclusively framed around, the theory of Mutually Assured Destruction. There have been some hot but localised crisis moments during the Cold War in which nuclear strategists were pressed into action. Short-range, low-yield battlefield nuclear weapons are an obvious concern in the Ukraine war. A whole of nuclear weapon fell outside the arms control treaties since the US withdrawal from the Intermediate-Range Nuclear Forces Treaty in 2019.

Patricia Lewis of the London-based policy institute Chatham House issued a note on the Ukraine war that posited that Nato would respond if nuclear weapons were used in the country. She said this would be on the grounds that the impact of such weapons crosses borders. This is to say nothing of the whole new set of thinking needed for containing and reacting to cyberattack threats that trigger nuclear arsenals or create false flags.

A P2V Neptune US patrol plane flies over a Soviet freighter during the Cuban missile crisis in 1962. Getty Images

The US dropped atom bombs on the Japanese cities of Hiroshima and Nagasaki in 1945. AFP

Another academic expert Ward Wilson wrote for the London-based European Leadership Network about a root-and-branch re-examination of the theory of nuclear deterrence.

There are no clear conclusions to be drawn from previous instances of deterrence. The most obvious example is the Cuban missile crisis of 1962, when then US president John F Kennedy threatened to use military force in response to the Soviet Union’s installation of nuclear-armed missiles on the communist-run island less than 800 kilometres from Florida. There is still a split between those historians who say Kennedy was a hawk pushing for retaliation and those who believe he favoured a blockade over retaliation.

There are even doubts in some quarters that then Japanese emperor Hirohito surrendered to the US-led allied forces in 1945 as a result of the atomic bombings of Hiroshima and Nagasaki. The orders given out to Japanese military two days after its surrender cited the Soviet Union entering the war against Japan – not the dropping of the "most cruel bomb" on two of its cities.

There is very little direct experience of the use of the weapon in war. On the other hand, according to Wilson, we can see the results of using artillery and missiles in an effort to break morale of a besieged population because there are plenty of examples of this type of bombing.

The effectiveness of nuclear weapons holds some keys to building adequate deterrence strategy. In the nuclear world, pretty much all there is to go on are tests and, in some senses, scenarios played out in exercises. Russia has ended some of its exercises with a tactical nuclear weapon, but when it comes to deterrence, those examples can be read two ways. Ultimately, there is psychological and emotional guessing that would underpin a nuclear stand-off. Classical deterrence is, however, focused heavily on the role of human judgement.

What if the person is flooded with anger? What if that anger recedes and rationality takes over? Can that equilibrium hold or will the anger come to the surface again? A threat to counter a potential attack might work at one hour but not the next day.

It is already known that escalations open the perils of miscalculation, misperception and misjudgement. There are no right or wrong answers, or at least, it isn’t clear what the right and wrong answers are. There are more likely just good and bad options.

For Mr Brenton, the difference is that the "Vladimir Putin I knew", who was the most single-minded, best-briefed, clear-thinking politicians on the scene, "would not have done this".

The complexity of deterrence, therefore, could not be more starkly challenged than at this moment in history.