Unnecessary Suffering

1868 St Petersburg Declaration

The principle is also known in other circles as the principle of superfluous injury or the principle of useless aggravation.

• It concerned the exploding bullet (i.e. bullets designed to explode on impact).

• Central to the principle is the aim to minimise the pain to combatants (note: do not refer to civilians, since they should not be subject to targeting in the first place).

• The importance of the Declaration was its novel introduction of a prohibition on a particular type of weapon.

• In addition, the reasoning of the Declaration is instructive:

  • The only legitimate objective is to weaken the forces of the enemy (distinction principle – focused on combatants; reaffirms that the combatant is a perfectly lawful target).

  • There is no restriction on how you can kill on the other side.

  • The rationale in relation to the sufferings of disabled men is the Principle of Unnecessary Suffering (POUS).

The critical issue arising from the 1868 St Petersburg Declaration is its normative approach:

• It established a mindset that a weapon was permissible so long as it was not formally ruled out by a declaration (or later, a treaty).

• This is a critical problem with the theorisation of the Principle of Unnecessary Suffering (POUS).

• The POUS is not presented as a good in itself; without a prohibition, the weapon is permissible.

Additionally, this arises out of the permissive nature of International Humanitarian Law (IHL): it lawfully permits the killing of an enemy combatant but places restrictions on the means of that killing.

Arts 22 and 23, Hague Regulations 1907

22. The right of belligerents to adopt means of injuring the enemy is not unlimited.

23. It is especially forbidden … (e). To employ arms, projectiles, or other material calculated to cause unnecessary suffering.

The Hague Regulations position is consistent with the same thinking that underpinning St Petersburg. The focus is on the experience of the combatant himself, and the kind of physical and psychological pain that is being inflicted.

Arts 35 and 36, AP1 1977

Article 35 – Basic Rules

1. In any armed conflict, the right of the Parties to the conflict to choose methods or means of warfare is not unlimited.

2. It is prohibited to employ weapons, projectiles, and materials and methods of warfare of a nature to cause superfluous injury or unnecessary suffering.

Article 36 – New Weapons
In the study, development, acquisition, or adoption of a new weapon, means, or method of warfare, a High Contracting Party is under an obligation to determine whether its employment would, in some or all circumstances, be prohibited by this Protocol or by any other rule of international law applicable to the High Contracting Party.

Note: Article 35 extends Article 22 of the Hague Regulations to refer to both methods and means of warfare.

• Additional Protocol I (AP I) has not been ratified by a number of nuclear-weapon States, including the United States, Iran, Pakistan, and Israel (which has also not signed).

• However, several of these States — including the US and the UK — have signed Nuclear Understandings in relation to AP I:

  • These understandings indicate that the rules established by AP I would not regulate or prohibit the use of nuclear weapons, but apply only to conventional weapons.

  • Compare: Vienna Convention on the Law of Treaties (VCLT) Article 18 — States that have signed or ratified a treaty must refrain from acts that would defeat the object and purpose of the treaty pending its entry into force.

ICJ in Nuclear Weapons (1996) Advisory Opinion

Elevates the POUS to a ‘cardinal principle’ of IHL (see [78]):

• “According to the second principle, it is prohibited to cause unnecessary suffering to combatants: it is accordingly prohibited to use weapons causing them such harm or uselessly aggravating their suffering. In application of that second principle, States do not have unlimited freedom of choice of means in the weapons they use.”

• Note: The ICJ here refers only to the means of warfare, but notably at [95] it refers to both ‘methods and means of warfare’.

The ICJ defines unnecessary suffering as “a harm greater than that unavoidable to achieve legitimate military objectives” ([78]).

• This reflects an intertwining of suffering with the doctrine of military necessity.

• In assessing this, consider:

  1. The objective suffering of the victim, together with

  2. The objective analysis of military necessity.

Rule 70, CILS (ICRC)

Rule 70. Weapons of a Nature to Cause Superfluous Injury or Unnecessary Suffering

The use of means and methods of warfare which are of a nature to cause superfluous injury or unnecessary suffering is prohibited.

The Customary International Law Study (CILS) restates the rules reflected in Additional Protocol I (AP I) and elevates them to a norm of customary international law (CIL) applicable to both international armed conflicts (IACs) and non-international armed conflicts (NIACs).

• In relation to NIACs, the CILS refers to Tadić (1995):

  • “Elementary considerations of humanity and common sense make it preposterous that the use by States of weapons prohibited in armed conflicts between themselves be allowed when States try to put down rebellion by their own nationals on their own territory. What is inhumane, and consequently proscribed, in international wars cannot but be inhumane and inadmissible in civil strife.”

• In relation to the POUS, the CILS makes the following statements:

  • “The prohibition of means of warfare which are of a nature to cause superfluous injury or unnecessary suffering refers to the effect of a weapon on combatants.”

  • “A relevant factor in establishing whether a weapon would cause superfluous injury or unnecessary suffering is the inevitability of serious permanent disability.”

  • “A related issue is the use of weapons that render death inevitable.”

  • “Although the existence of the prohibition of means and methods of warfare which are of a nature to cause superfluous injury or unnecessary suffering is not contested, views differ as to whether the rule itself renders a weapon illegal or whether a weapon is illegal only if a specific treaty or customary rule prohibits its use.”

    • There are two different ‘understandings’ of the rule:

      1. The rule itself is the basis of illegality; or

      2. Illegality derives only from a specific treaty or customary rule (this is the position taken by France and Russia in the Nuclear Weapons Advisory Opinion).

Chemical weapons

1925 Geneva Gas Protocol

‘First Use’ Reservation entered into by France and other States, indicating they regard themselves as bound but released from the prohibition if chemical weapons are used against us.

Cf. 1993 Chemical Weapons Convention (CWC), in respect of which no reservations were allowed.

Rule 74, CILS - The use of chemical weapons is prohibited.

Nuclear Weapons Advisory Opinion ICJ (8 July 1996)

Three stages of analysis:

The court does not do a pure St Petersburg analysis

1. Is there a specific treaty or prohibition of nuclear weapons? - can we point to a general treaty that outlaws nuclear weapons - NO

   1. Looked at the Gas Protocol and said it doesn't address Nuclear weapons

   2. Paragraph 58 - it says there are some treaties dealing with nuclear weapons but none specifically address nuclear weapons (but when you examine them, they are not about general use)

2. If not, is there a customary law prohibition? NO

   1. Para 64 - tried to look at the practice, and the non-use of nuclear weapons by states since 1945. The court says that it doesn't not want to say anything about the "policy of deterrence"

   2. The non-use of nuclear weapons might be used to say that there is a customary prohibition, but we cannot prove that. We would need to demonstrate that the reason why states aren't using it needs to be proven that it is a customary prohibition. They can't though, because it may be a 'deterrence' situation. The court can't prove that states are considering there is a customary prohibition. Have to weight "specially affected states" that have nuclear weapons and their behavior.

      1. States that have chosen not to develop nuclear weapons…

   3. The court looks to UNGA resolutions - the Court declares that several of the resolutions say that that nuclear weapons should be prohibited, and that they need to create a treaty. But there have been many negative votes and abstentions.

3. Principles and rules of IHL (the cardinal principles)

   1. Para 78 - protection of the civilian population and objects; states must never use weapons that are incapable of distinction. The court is imagining an attack in a dessert, or in the sea that could be contained to just combatants.

      1. The principle of unnecessary suffering

         1. The court never gets to the point where it can look at the impact of the weapon on combatants. It does not give us the analysis that we are due given St Petersburg…

      2. They mention the Martens clause, but don't actually use it to look at the principles of humanity, etc. Russia seemed to disown the Martens clause saying there is no relevance for it with regard to nuclear weapons.

         1. It was galvanized behind the disarmament treaties after St Petersburg.

      3. The ICC are much more proactive on the power and potency of Martens…here we just get "rhetorical flourish".

ICJ - Nukes AO refers to 2 cardinal principles

Recognises two ‘cardinal principles’ of IHL: distinction and the POUS

Nuclear weapons AO Dissenting (Judge Higgins)

The Court’s effective non liquet (‘lacuna in the law’) on a key issue: whether nuclear weapons in extremis (self-defence) would be lawful or unlawful.

• The Court fails to explain its reasoning in reaching this conclusion, despite having noted general principles contrary to IHL.

• Higgins observes that unnecessary suffering is not the same as horrendous suffering: the POUS concerns the limitation of means used against a legitimate target.

• The principle requires a balancing between military necessity and humanity: what military necessity is so grave as to justify the level of suffering caused by nuclear weapons?

• Beyond combatants, the Court should have considered the protection of civilians: would the principle of distinction preclude an attack if collateral civilian casualties were unavoidable? (See also the proportionality principle.)

• What does the term ‘generally’ mean? What exceptions are implied? The dispositif raises all these questions but answers none of them.

Nuclear weapons AO Dissenting (Judge Weeramantry)

He links the Principle of Unnecessary Suffering (POUS) to the Martens Clause, suggesting that it:

• “gave classic formulation to [the POUS] in modern law, when it spelt out the impermissibility of weapons incompatible with ‘the laws of humanity and the dictates of public conscience.’”

Nuclear weapons AO Dissenting (Judge Koroma):

• Refers specifically to the effects following Hiroshima and Nagasaki as ‘elements of fact’: indiscriminate killing of civilians.

• The uniquely devastating characteristics of nuclear weapons would inevitably render any use of such weapons inconsistent with the principles of IHL referred to by the Court and the Court’s own reasoning.

• The concept of ‘State survival’ (invented by the Court) is presented as an exception to IHL.

• The unlawfulness of nuclear weapons is not predicated on the circumstances of use, but on the unique and established characteristics of the weapons, which would violate international law ‘under any circumstance’.

Nuclear Weapons AO - personal analysis

Analysis:

• The ICJ elevates the unnecessary suffering rule to the status of a ‘cardinal principle’ of IHL, alongside the principle of distinction.

• The reasoning adopted by the majority opinion is deeply unsatisfactory and fails to fully apply or engage with the IHL principles the Court itself invokes.

• The best explanation for the 1996 ICJ decision on Nuclear Weapons is by reference to the framework of the Principle of Unnecessary Suffering (POUS) set out in the 1868 Petersburg Declaration:

  • Notwithstanding the descriptor in [35], the Court does not bring itself to banning the weapon outright.

  • Its analysis looks generally at effects on combatants and civilians but does not actually apply the framework/test of immediate/imminent pain to the combatant.

• POUS is not designed as a normative principle with its own unyielding power. If it were, the Court would have stated that these weapons, by their nature and considering the pain caused to combatants, were prohibited.

• In some respects, IHL is ‘posing as law’.

• The principles of IHL are rallied almost as an afterthought by the Court. The suggestion is that since there are no hard (legal) sources in play, the Court will consider these lurking principles — albeit not to any pragmatic effect.

• The Court’s non liquet cuts across the traditional separation of jus ad bellum and jus in bello.

McCormack (1997) - Nuclear AO analysis

• McCormack (1997) also notes that “[t]he Court has helped legitimize a compartmentalization of international law by reaffirming that the general principles of customary international humanitarian law do not automatically apply to specific weapons […] the Court’s inability to translate the general principles into a substantive prohibition on the use of nuclear weapons ought to raise concern.”

Treaty on the Prohibition of Nuclear Weapons [TPNW] 2017

None of the nuclear-armed nations have expressed support (US, UK, France and Russia have expressly indicated they oppose it).

o See preamble - ‘mindful of unacceptable suffering of and harm caused to the victims of nuclear weapons (hibakusha), as well as those affected by the testing of nuclear weapons’

Chapter 22 of CILS

Notes finding above re no customary prohibition of nuclear weapons.

o “the Court being the principal judicial organ of the United Nations, the ICRC had to take due note of the Court’s opinion and deemed it not appropriate to engage in a similar exercise at virtually the same time.”

ICJ AO Nuclear Weapons - on proportionality

41. The submission of the exercise of the right of self-defence to the conditions of necessity and proportionality is a rule of customary international law.

ICJ AO Nuclear Weapons - distinction

Thus, methods and means of warfare, which would preclude any distinction between civilian and military targets, or which would result in unnecessary suffering to combatants, are prohibited.

Personal analysis - as applied to automated weapons systems

With the rapid development of automated weapons systems and the ongoing race toward Artificial General Intelligence (AGI) — AI systems that possess the ability to understand, learn, and apply intelligence broadly at or beyond human levels — the international community faces similar legal and ethical challenges as with nuclear weapons. Automated weapons systems have the potential to deliver lethal force at unprecedented speed and scale, with minimal or no direct human oversight. Their capacity for autonomous target selection and engagement raises the risk of indiscriminate or disproportionate destruction, amplifying the human and environmental cost of warfare.

• The Principle of Unnecessary Suffering (POUS) is relevant because automated weapons could cause unpredictable, excessive, or superfluous injury and suffering, especially if they malfunction or make flawed decisions.

• As with nuclear weapons, the military necessity justification will likely take a stronghold over the conversation.

• Given the uncertainty and risks, an international tribunal or court would likely face a similar dilemma as in the Nuclear Weapons AO: whether to prohibit such weapons outright, or await more defined norms. However, the growing international debate, ethical concerns, and calls for bans (e.g., campaigns against lethal autonomous weapons) strengthen the case for early prohibition or strict regulation.

• In this context, the Martens Clause — which appeals to “the laws of humanity and the dictates of public conscience” — may need to play a stronger, more proactive role in deciding how ‘humanity’ should be interpreted in the mass proliferation of AI-powered warfare.