Contesting the Legality of Nuclear Weapons

Publication Date: 
Wednesday, August 12, 2015

Nuclear weapons are once again on the global agenda. Last month, Iran reached an agreement with the US and five other world powers, intended to halt its development of nuclear weapons. Last week, Japan commemorated the seventieth anniversary of the atomic bombings of Hiroshima and Nagasaki during the final days of World War II, the first use of nuclear weapons in history. Survivors recalled the horrific and enduring effects of the atomic bomb, some of which have lasted generations. “[E]ver since 1945,” writes The Guardian, “nuclear weapons have transformed the global strategic landscape and even the very notion of war.” And ever since the narrowly-averted nuclear showdowns between the US and Soviet Union during the Cold War, many states and civil society organizations have endeavored to control the spread of nuclear weapons and reinforce a taboo against their use. Yet states have failed to reach a consensus around their elimination or prohibition, and the legality of nuclear weapons remains a matter of considerable debate in international law. This post highlights the continued relevance of this debate to the humanitarian sector.

Due to the lack of binding agreement among states regarding the elimination of nuclear weapons, there is no universal prohibition on such weapons in international treaty or customary law, as the International Court of Justice (ICJ) noted in its 1996 Advisory Opinion on the legality of nuclear weapons. Furthermore, the number of “treaties dealing exclusively with acquisition, manufacture, possession, deployment and testing of nuclear weapons, […], certainly point to an increasing concern in the international community with these weapons”(para. 62), potentially foreshadowing – but not constituting – a general prohibition to come. Nonetheless, the Court stressed the unique character and destructive nature of nuclear weapons:

These characteristics render the nuclear weapon potentially catastrophic. The destructive power of nuclear weapons cannot be contained in either space or time. They have the potential to destroy all civilization and the entire ecosystem of the planet. […] In consequence, […] it is imperative for the Court to take account of the unique characteristics of nuclear weapons, and in particular their destructive capacity, their capacity to cause untold human suffering, and their ability to cause damage to generations to come (para. 35-36).

While international humanitarian law (IHL) seeks to limit the potential harm to civilians in armed conflict, it does not specifically address nuclear weapons. Given such weapons’ unique destructive power, however, their use would seem to necessarily violate several of the cardinal principles of IHL, namely:

  • Distinction, which requires that combatants distinguish in their targeting between combatants and civilians, and prohibits attacks directly at civilians or civilian objects, as well as indiscriminate attacks [AP I, art. 48, 51];
  • Proportionality, which requires that the anticipated collateral damage from an attack not be excessive in relation to the concrete and direct military advantage expected [AP I, art. 51];
  • The prohibition on means or methods of warfare that are “of a nature to cause superfluous injury or unnecessary suffering,” as well as weapons that cause “widespread, long-term and severe damage to the natural environment” [AP I, Art. 35]; and
  • The obligation to take feasible precautions in attack to minimize harm to civilians and civilian objects [AP I, art. 57].

It is difficult to imagine a nuclear strike complying with these principles, given the immense short and long-term harm these weapons have been seen to cause in Hiroshima and Nagasaki, as well as in subsequent studies; though advocated by some, “tactical” or low-yield nuclear weapons designed to better comply with these principles remain far-fetched. The ICJ acknowledged this tension in its Advisory Opinion, though declined to settle the matter:

In view of the unique characteristics of nuclear weapons, to which the Court has referred above, the use of such weapons in fact seems scarcely reconcilable with respect for such requirements. Nevertheless, the Court considers that it does not have sufficient elements to enable it to conclude with certainty that the use of nuclear weapons would necessarily be at variance with the principles and rules of law applicable in armed conflict in any circumstance (para 95, emphasis added).

Ultimately, the Court declined to “reach a definitive conclusion as to the legality or illegality of the use of nuclear weapons by a State in an extreme circumstance of self-defence, in which its very survival would be at stake”(para. 97).

This narrowly reached decision thus left open the possibility of legal use in cases of self-defense, and has been criticized by many observers for its ambiguous ruling on the legality of nuclear weapons. In 2011, the International Red Cross and Red Crescent Movement’s Council of Delegates concluded that “it is difficult to envisage how any use of nuclear weapons could be compatible with the requirements of international humanitarian law, in particular the rules of distinction, precaution and proportionality.” As such, many organizations advocate for a ban on nuclear weapons, as ICRC President Peter Maurer underscores:

Today the best action States can take is to fulfil their existing obligations and engage in the negotiation of a legally binding agreement or set of agreements that would outlaw the use of nuclear weapons and at the same time lead to comprehensive disarmament.

As technology develops over time, other weapons have also raised questions of compliance with IHL, including, for example, the expanded military use of unmanned aerial vehicles (“drones”) by the US in recent years. Yet nuclear weapons predate the development of modern IHL; rather, it was their unique deterrent function that made states so reluctant to eliminate them. While the end of the Cold War brought hope of a new era free from the shadow of nuclear war, the continued possession and development by states of nuclear arsenals, amidst instability in contemporary international relations, remains a relevant concern for humanitarian actors, not only global security analysts. On the 70th anniversary of Hiroshima and Nagasaki, the debate over the legality of nuclear weapons continues, but their catastrophic humanitarian consequences are well known. As the ICRC emphasizes, the scale and mass of devastation caused by a nuclear weapon poses serious challenges for humanitarian response, with local capacities likely to be destroyed or quickly overwhelmed, and “no effective capacity at the international level to deliver appropriate humanitarian assistance to survivors if nuclear weapons were ever to be used.” As efforts towards nuclear disarmament continue in the political sphere, legal and humanitarian efforts are equally critical to address one of the greatest threats to humanity.

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