The Expansionist Approach of Self-defence has Undermined International Law

[Benazir Jatoi is a UK-based human rights lawyer from Pakistan. She has consulted with the UNFPA and UNWomen, Pakistan.]

It is essential that countries critically re-examine the expansionist approach to self-defence. This is because it has become an arbitrary tool of affluent military powers to justify war and set dangerous precedents of raw and brutal force, causing devastating human suffering, primarily in countries of the Global South. But more fundamentally, it is undermining Article 2(4) of the UN charter, the blanket provision which prohibits states from the “threat or the use of force” against another state.  

The right to self-defence and where it is situated with and around Article 2(4) has been extensively debated: Marko Milanovic argues that it is one of the narrow exceptions to Article 2(4), while Adil Haque observes that self-defence as an exception to the exception: 

“Article 2(4) prohibits the use of force, but makes an exception for armed force permitted within that structure. That structure generally requires the Security Council to authorize armed force, but makes an exception for self-defense if an armed attack occurs before the Security Council takes necessary measures. So Article 51 is an exception to an exception to Article 2(4).”

Whether used as an exception to Article 2(4), a defence that is subsidiary to the collective security framework or an exception only when the Security Council is unable to take the necessary measures to ensure peace, the premise of self-defence has become the convenient hatch key unlocked far too easily to justify attacking (yet) another country. It is being tapped into on a regular basis and its frequency and the manner in which it is being triggered has colloquized the term itself, making it devoid of any legal meaning. 

The term self-defence has morphed from being a restrictive and narrow principle, in which the rules of proportionality and necessity follow its use, to gaining rubber band elasticity, depending on the military might of the country that interprets its meaning. In this regard, self-defence has had two lives. One is the pre-9/11 understanding of self-defence and the other a varied and growing understanding and use of self-defence after 9/11. 

The Pre-9/11 Understanding of a State’s Right to Self-defence

Nicaragua v. United States of America was understood to hold the widely accepted view of self-defence. In its judgement the ICJ re-enforced Article 2(4), noting that territorial sovereignty is the right of all States and the principle of non-intervention in matters of domestic jurisdiction of a State must be upheld. 

This case illustrates how self-defence was once widely understood:

1. The right to self-defence can only be triggered where a clear and grave violation by another state takes place. 
2. No activities should jeopardise the principles of upholding territorial integrity and of the “non-intervention in matters within the domestic jurisdiction of a State.” 
3. Self-defence by State A requires evidence that State B has violated its territory. This requires State B to be substantially involved in the said violation, and simultaneously, excludes non-state actors as proxy representatives of State B. The ICJ notes that assistance to rebels in the form of provision of weapons or logistical support does not suffice as substantial involvement.
4. The Security Council Framework is considered well established as a foundational system, with clearly defined processes for collective prevention or halting of violence. This implies that this is the institutional mechanism on which states should rely to both prevent violations, and hold states and non-state actors to account should a violation occur. One of the preliminary points put forward by the United States in this case stated that an allegation of unlawful force could only be established by the Security Council and the Court cannot effectively deal with this question “without overstepping proper judicial bounds”. This reveals the widely held view, pre 9/11 of the importance of the Security Council framework as an essential requirement to determine violation of Article 2(4). 
5. And lastly, it can be concluded that Article 51 is not a standalone rule but only applies within and around the context of Article 2(4). In other words, without engaging Article 2(4), self-defence, in its legal sense, cannot be triggered. 

The Post-9/11 Understanding of a State’s Right to Self-defence

The attack on Afghanistan after 9/11 changed the established position on when self-defence is triggered. As Christine Gray notes in International Law and the Use of Force, “the US invasion of Afghanistan…led to a fundamental reappraisal of the law on self-defence.” 

The Afghanistan invasion in 2001 opened the floodgates to allow the expansion of the definition of self-defence. Since then, with every new geopolitical situation with which the United States and its allies have been confronted, the understanding of self-defence has been reshaped significantly. Its expansion began with the inclusion of non-state actors to justify military action against Al-Qaida in Afghanistan. George Bush Jr noted at the time, “if any government sponsors the outlaws and killers of innocents, they have become outlaws and murderers, themselves.” 

The definition of self-defence further expanded when the US remained in Afghanistan to ensure Al-Qaida did not re-gain its previous military capacity. This allowed the interchanging of self-defence with nation building, and for approximately 20 years it became impossible to tell if national building by the US and its allies had become a form of self-defence. In addition to Afghanistan, the Iraq invasion in 2003, the Gaza genocide in 2023 and the ongoing Iran attacks in 2026 are key examples of self-defence being vocalised as reasons for the violation of another sovereign territory. 

Self-defence is increasingly becoming a loose and arbitrary term, reshaped by powerful Western governments, based on geopolitics and allyship and, worryingly, at the expense of international law. It is ironic that countries that emphasise the rule of law and have strong legal institutions are the ones actively reinterpreting the international law, particularly self-defence. This is not limited to discussions seeking a re-interpretation due to changing global realities. It is action oriented – without proper international consensus. 

The ever-changing reconfiguration of the meaning of self-defence and its various justifications – from pre-emptive attacks, to imposing democratic ambitions for the society being invaded – has led to two things. Firstly, it has left a glaring inconsistency between established international law and actual practice. The subjective and arbitrary interpretation of self-defence based on geopolitical gains, without scrutiny from established Security Council frameworks and the ICJ precedents, is forcing a large gap between the textbook meaning of self-defence and actual practice by Western governments.  

Secondly, it risks rendering Article 2(4) almost redundant. Marko Milanovic succinctly conveys this point – that to trigger Article 51, Article 2(4) must be engaged.  Bypassing or easily staying aside, the most fundamental principle which sits at the core of international law (that of refraining from threatening or using force against another State) makes the law of the jungle more likely. It also disadvantages countries of the Global South as the selective application of the law has led to these countries being the primary targets by powerful foreign militaries, like the United States, its European allies and Israel. 

Recent conflicts show that Article 51 has begun to fall into a layperson’s terminology, used only to invoke emotions and to build a political narrative to justify war. The legal definition of self-defence and the requirements that follow the exception – that of establishing an imminent threat, of engaging the Security Council or other institutional mechanisms – become futile. By side stepping this essential principle of Article 2(4), the strict principles of necessity and proportionality required under Article 51 become unnecessary to follow by the country violating another territory. And even more importantly, by ignoring these principles, it becomes near impossible to hold to account States that cross the limitations under which Article 51 operates.  

Take the most recent attacks on Iran by Israel and the US. Various haphazard reasons have been given to trigger self-defence. One stance is that the US launched attacks to prevent retaliation for fear that Iran would respond to planned Israeli attacks. This was then contradicted when it was said the US attacked Iran pre-emptively because of fears that Iran may strike first. Other reasons range from the elimination of Iranian nuclear and military capabilities to the elimination of Tehran’s capability to support proxy groups in the region, to more vague explanations, ranging from freedom for the Iranian people and regime change. 

The evolving justifications put forward by the White House all consistently attempt to invoke self-defence and simultaneously undermine the blanket provision that force cannot be used against another country. However, shifting narratives risk resembling a form of legal opportunism. Like a roulette wheel – if spun enough times it may land close enough to the legal threshold of self-defence, even if none meaningfully meet it. 

Political justifications for attacking Iran and debates in most Western capitals confirm that the decision on whether to join the US and Israel was never based on the principles of international law. Tony Blair, the ex-Prime Minister of the United Kingdom, has recently said Britain should have supported America from the very start in its attacks on Iran. The reply from the British government has been in the same realm – that Britain will look after its own interest, not that of the United States. These statements reiterate that the decision is not based on law, but on geopolitics. Otherwise, the debate would be: is this war legal under established international law? Is there an imminent threat from Iran that establishes a case to violate Article 2(4)? And following on from this, whether that violation is grave and evident enough to necessitate the use of force without engaging any other established means of ensuring that war would be the last resort? The targeting of desalination plants, schools and hospitals by the US and Israel confirm a reliance on geopolitical calculations, without much reliance or reference to the principles of international law. 

The restrictive approach to Article 51 would have required two things: firstly, establishing that a grave violation – which justifies violating Article 2(4) – has taken place. Secondly, that no other means could have been resorted to, in order to avoid the violation of Article 2(4). None of these have been satisfied to date, and in the process, Article 2(4) has been breached as Iran’s sovereign integrity and political independence have been violated without any clear legal justification.    

Regime change, one of the many reasons for violating Article 2(4), shifts the questions greatly: what and who requires satisfying that the regime has been successfully changed? Is it Western taxpayers? Western governments? The President of the United States? Similarly, who determines what freedom looks like? Is it Western, liberal ideas that define freedom? Is it liberation in the form of ‘hijab-less’ women? A secular government? Or a government more open to ‘business’ with the Western world? None of these questions, nor their answer fit into the legal requirements of international law. Because the initial reasons for triggering self-defence remain vague and outside restrictive legal requirements, the reason to stop military action becomes vague, politically motivated and further from legal reasoning. This same vacuum, without any coherent legal framework under which decisions were made, led to an almost 9 year invasion of Iraq and a 20 year one in Afghanistan. 

International law mechanisms are far from perfect. They are slow, cumbersome and rely on the goodwill of countries. Its foundation is based on colonialism and how states interact with one another – hence the most powerful countries, with imperialist pasts, are rarely held accountable for violations that occur against other countries and the veto power of a few countries govern how international law is practised. The subordination of non-Western countries is a carefully crafted design of the international system and the reason we have seen aggression by the most powerful Western countries against other states without little or no accountability from established international mechanisms. There is no double that an exercise in the decolonisation of international law and the United Nations is required. 

Having said that, we do not need less law, less rules or less mechanisms to allow for more arbitrary and politically motivated reasons to violate established law. In fact, we need more of it, more evenly applied laws, more historical context, more scrutiny and more accountability. Without it, as we are already witnessing, there is a danger of strongmen, mighty armies and a world on the brink of absolute chaos becoming the new reality. 

It would be myopic to view self-defence merely in legal and textbook terms alone. It must also encompass the most recent actions of countries that continue to use it to justify war.  If we do not address the discrepancies – either by altering the legal understanding of self-defence or holding to account those that violate it, we will be slipping further into a world where, yet again, the most powerful countries, invade and destroy another country, for one simple reason: because they can and then, can get away with it.