The late Christopher Hitchens once referred to nuclear bombs as ‘apocalyptic weapons’. His words were far from hyperbole. In an interview in the Guardian, Sunao Tsubi, described how he was convinced that he had “entered a living hell on earth” after witnessing the ruination of Hiroshima by “Little Boy” – an atomic bomb loosed by an American plane on 6 August 1945. It erased more than 140,000 lives.
In spite of the horrors of Hiroshima and Nagasaki, more than 16,000 nuclear weapons are still in existence. The United Kingdom lays claim to just over 200 warheads. During the course of the general election the question of whether we should ever put our arsenal to use was the subject of fierce debate. In one particularly striking interview, Piers Morgan asked the following question to Dianne Abbott:
What if ISIS … get a nuclear weapon and are about to use it and you know where they are and you know where they are going to fire it from?
He proceeded to berate Abbott for not stating, conclusively, that her party would order a pre-emptive, nuclear strike on a terrorist group situated within another state.
In my view, she was perfectly correct not to do so. His hypothetical question failed to account for a huge number of variables, including the fallibility of human intelligence and the levels of collateral damage involved. To press the nuclear button on Piers Morgan’s terms, however, would not only be morally vacuous, but illegal.
When it comes to warfare, international law consists of three distinct components:
1. The legal principles states must consult before using force (jus ad bellum);
2. International humanitarian law, or the legal principles states must consult during a war (jus in bello); and
3. The largely theoretical principles governing what happens after war (just post bellum).
In terms of the first set of rules, while it is clear that states have the right to defend themselves, since the 18th century it has only been permissible to carry out a pre-emptive strike in the face of an imminent threat. While some have sought to widen the rule, there is scant support for such a move. It seems, therefore, that without flawless intelligence indicating an immediate nuclear attack Morgan would be advocating a pretty serious violation of international law.
Assuming that we did receive such perfect intelligence, what do the laws governing our conduct during war have to say? In 2005, Jean-Marie Henckaerts and others produced the most comprehensive study of international humanitarian law to date. The first volume, which runs to some 600 pages, contains just a single leaf on nuclear weapons. Indeed, while treaties exist banning all manner of weapons deemed likely to cause superfluous suffering, there is no comprehensive ban on nuclear weapons.
Despite the lack of any specific ban, the use of nuclear weapons would still be illegal in most circumstances. This is because the use of such an indiscriminate weapon will usually violate the principle of distinction, which requires armed forced to distinguish between legitimate (military) and illegitimate (civilian) targets.
In what circumstances, though, might it be legitimate to make use of nuclear weapons? That was the question posed by the United Nations General Assembly to the International Court of Justice in 1994. The resulting advisory opinion makes for a fascinating read.
To the dismay of many, the majority opinion refused to rule out the use of nuclear weapons per se. Rather, it found that a state may still have the right to use such a weapon in an “extreme circumstance of self-defence, in which its very survival would be at stake”. The said state would nonetheless be bound by the legal principles detailed above.
In his dissenting opinion, Judge Schwebel suggested that the majority view was too restrictive. He proposed two situations in which the use of a nuclear weapon might not violate the above principles. First, the use of a small, tactical nuclear weapon against a submarine. Second, against a battalion situated in a remote desert.
The use of nuclear weapons in the above situations could potentially satisfy the principles of distinction and military necessity. However, it is difficult to see how using such a weapon would be proportionate. Importantly, the majority opinion dealt with this point by making clear that a proportionality assessment must factor in environmental considerations:
[T]he environment is not an abstraction but represents a living space [and] the general obligation of States to ensure that activities within their jurisdiction and control respect the environment of other States … is now part of the corpus of international law … States must take environmental considerations into account when assessing what is necessary and proportionate in the pursuit of legitimate military objectives.
Thus, even if a legitimate target is discerned, it is unlikely to be lawful to use a nuclear warhead which could incinerate an area the size of a city, rendering it uninhabitable.
It is pertinent to say a little something, at this juncture, about the jus post bellum. The importance of developing legal principles which govern our activity after a war has taken place has gained traction in recent years, particularly as a result of the West’s misadventures in the Middle East.
In this respect, some theorists have attempted to establish an obligation on participants in war to restore any environmental damage which they cause. If such a principle were to crystallise, while it would not render the use of nuclear weapons illegal per se, it would make their use vastly more expensive, to the point of being untenable. Douglas Lackey also suggests that placing such constraints within the body of the laws of war would incentivise military commanders to take them seriously.
As it stands, international law appears to render the use of nuclear weaponry illegal in all but the most exceptional circumstances. However, the potency of nuclear deterrent theory, coupled with a judicial reticence to pronounce on controversial questions, is likely to preclude an explicit ban for at least the foreseeable future.