Introduction
The regulation of weapons and the use of force in international law has traditionally been seen as the domain of International Humanitarian Law (IHL), particularly during armed conflict. The assertion by commentators such as Casey-Maslen (2015) that International Human Rights Law (IHRL) provides an "overarching international legal framework" for determining the legality of weapons is therefore a significant challenge to this established view. This essay will critically reflect on the relationship between these two bodies of law. It will argue that while IHL and IHRL offer differing safeguards, their concurrent application generally provides greater and more comprehensive protection, particularly in complex situations that blur the lines between peace and war. This argument will be developed by examining the regulation of weapons, the prohibition of torture, and the prohibition of sexual violence. It will be shown that while the combined application of both disciplines has distinct advantages, it also creates practical challenges, particularly regarding the rules on the use of force.
The Traditional View and the Lex Specialis Principle
The conventional understanding of the relationship between IHL and IHRL is based on a division of application. IHL is considered the specific law governing situations of armed conflict, while IHRL applies at all times, including peacetime. This has led to the argument that during an armed conflict, IHL acts as lex specialis (specific law), which takes precedence over the more general rules of IHRL. The logic is that IHL is better tailored to the unique realities of warfare, providing specific rules on targeting, detention, and the means and methods of combat that are not found in IHRL.
However, the International Court of Justice (ICJ) has clarified that this does not mean IHRL ceases to apply altogether. In its Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons, the Court stated that the protection of the International Covenant on Civil and Political Rights (ICCPR) does not stop in times of war (ICJ, 1996, para. 25). It confirmed that the right to life is not to be interpreted in isolation from IHL, meaning that a death that is not an arbitrary deprivation of life under IHL is also not a violation of the right to life under IHRL. The ICJ reaffirmed this position in its Advisory Opinion on the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, holding that IHRL is applicable in occupied territories, with IHL applying as the lex specialis where specific rules for occupation exist (ICJ, 2004, para. 106). Therefore, the modern view is not one of mutual exclusion, but of co-application, where IHRL provides a baseline of protection that is supplemented or modified by the specific rules of IHL during conflict.
Differing Safeguards: Weapons Law and the Use of Force
The divergence between the two legal regimes is most apparent in the rules governing the use of lethal force and the legality of weapons. IHL is designed to regulate conduct between warring parties. Its primary rules on weapons prohibit those that are inherently indiscriminate or of a nature to cause superfluous injury or unnecessary suffering (Additional Protocol I, 1977, Arts. 35, 51). IHL permits the targeting and killing of enemy combatants and civilians directly participating in hostilities, not as a last resort, but as a standard feature of military operations.
In contrast, IHRL, which primarily governs state action against individuals under its jurisdiction (including in law enforcement operations), sets a much higher threshold. The right to life, enshrined in instruments like Article 2 of the European Convention on Human Rights (ECHR), permits the use of lethal force by state agents only where "absolutely necessary" to protect others from unlawful violence (McCann and Others v UK, 1995). This is a standard of last resort, requiring a strict assessment of necessity and proportionality.
The concurrent application of these standards provides greater protection in situations that fall into the grey area between classic armed conflict and peacetime policing, such as counter-terrorism operations or managing civil unrest in an occupied territory. In such scenarios, applying only the permissive targeting rules of IHL would be inadequate. The IHRL framework demands that force only be used when essential, providing a more protective safeguard for individuals who may not be traditional combatants. However, this also creates a distinct disadvantage: legal uncertainty. A soldier operating in such an environment may be unclear whether they should apply the IHL rules of engagement or the more restrictive IHRL standard. This can lead to operational confusion and a risk of either excessive force or a failure to act when necessary, potentially endangering both civilians and military personnel (Akande, 2012).
Reinforcing Safeguards: Torture and Sexual Violence
While the rules on the use of force present a clear divergence, in other areas the two bodies of law are mutually reinforcing, providing greater safeguards through their combined application. The prohibition of torture is a prime example. IHL unequivocally prohibits torture and cruel, inhuman, and degrading treatment in all circumstances, with no exceptions (Geneva Conventions 1949, Common Article 3). Similarly, IHRL contains an absolute and non-derogable prohibition on torture, as seen in Article 7 of the ICCPR and the UN Convention Against Torture.
Here, the two frameworks do not offer differing standards but a single, unified norm. The advantage of this overlap is the strengthening of the prohibition. It removes any legal ambiguity and sends a clear message that torture is illegal under all circumstances, whether in peacetime, during a riot, or on a battlefield. The dual prohibition also offers multiple enforcement mechanisms. A violation can be prosecuted as a war crime under IHL (e.g., at the International Criminal Court) and simultaneously be the subject of a claim against the state before a human rights body, such as the European Court of Human Rights. This creates a stronger web of accountability.
A similar complementary relationship exists regarding the prohibition of sexual violence. IHL expressly prohibits rape, enforced prostitution, and any other form of indecent assault as grave breaches of the Geneva Conventions and as war crimes (Rome Statute, 1998, Art. 8). IHRL also protects individuals from sexual violence through the right to be free from torture and inhuman treatment, the right to personal security, and the right to privacy. The advantage of this dual protection is that it provides different legal angles for redress. IHL focuses primarily on individual criminal responsibility for acts committed during conflict. IHRL, on the other hand, imposes a positive obligation on states to prevent, investigate, and punish acts of sexual violence, and to provide remedies to victims. This means a state can be held responsible under IHRL for a systemic failure to protect people from sexual violence by its armed forces, even if specific perpetrators cannot be identified or convicted under IHL. This creates a more holistic system of protection and accountability that would not exist if only one body of law applied.
Conclusion
In conclusion, the protections offered by International Human Rights Law and International Humanitarian Law are not mutually exclusive but increasingly intertwined. Their concurrent application provides a more robust and comprehensive legal framework for regulating state violence than either discipline could alone. The safeguards they offer are sometimes different and sometimes complementary. In the context of weapons law and the use of force, the stricter IHRL standard of "absolute necessity" offers greater protection than IHL's targeting rules, but this advantage comes with the disadvantage of practical uncertainty in complex operational environments. In other areas, such as the absolute prohibitions on torture and sexual violence, the two regimes reinforce each other, strengthening the norm and providing multiple avenues for accountability. The primary advantage of applying both disciplines is the creation of a more complete system of protection that can fill legal gaps and hold both individuals and states to account. While challenges of interpretation and implementation remain, the trend towards an integrated approach, as suggested by Casey-Maslen (2015), ultimately offers greater safeguards for individuals caught in the crossfire of state violence.
References
Akande, D. (2012) 'The Gaps in the Law of Occupation', in A. Clapham and P. Gaeta (eds.), The Oxford Handbook of International Law in Armed Conflict. Oxford University Press.
Casey-Maslen, S. (2015) 'Weapons Under International Human Rights Law', Geneva Academy of International Humanitarian Law and Human Rights, Academy Briefing No. 4.
European Convention on Human Rights (1950) 213 UNTS 221.
Geneva Conventions of 1949 and Additional Protocols of 1977.
International Court of Justice (1996) Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, ICJ Reports 1996, p. 226.
International Court of Justice (2004) Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion, ICJ Reports 2004, p. 136.
International Covenant on Civil and Political Rights (1966) 999 UNTS 171.
McCann and Others v United Kingdom (1995) 21 EHRR 97.
Rome Statute of the International Criminal Court (1998) 2187 UNTS 90.
