Since the attacks of September 11, 2001, there has been discussion over whether powerful states are undermining the legal system established in 1945. Applying pre-emptive force in order to defend oneself goes against the principal provisions of the UN Charter. As a result, there have been more violations of international law, a departure from the rules generally accepted by everyone, and an increased emphasis on political agreements.
In answering that question, let us go back in history, noting that the rationale for the use of force predates the UN Charter and the formulation of the established rules of international law regarding the right to anticipatory self-defence. The best-known instance of this is the Caroline case of 1837, in which it was decided that the principles of necessity, proportionality and imminence must serve to guide self-defence. These points were later made clear in the diplomatic correspondence between the U.S. Secretary of State Daniel Webster and the British representative, Lord Ashburton; the standard set forth was that the necessity for self-defence must be “overwhelming, leaving no choice of means and no moment for deliberation.”
Article 51 of the UN Charter recognises the right of individual or collective self-defence in the event of an armed attack. Any actions taken in self-defence must be reported right away to the Security Council, and this right lasts until the Council acts to maintain peace and security. Article 51 is a specific exception to the Charter’s general ban on the use of force. There is still debate about whether international law permits anticipatory self-defence against an imminent attack, but a distant or speculative threat alone does not justify the use of force.
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On the contrary, the Charter’s Article 2(4) lays down a basic ban on the part of states in the following way: they must “refrain in their international relations from threatening or using force against the territorial integrity or political independence of any state or in any other way inconsistent with the purposes of the United Nations.”
The framers never fully expected the emergence of non-state terrorist groups, the spread of weapons of mass destruction, or the technological capabilities that allow for long-range, accurate, and swift attacks, which are characteristic of warfare in the twenty-first century.
The argument for the use of pre-emptive force dates back to 2001 as a response to the Al-Qaeda attacks of September 11. In the wake of those attacks, the United States and its allies began what was called the ‘War on Terror’. The idea of the ‘War on Terror’ became widely accepted during the administration of George W. Bush, who in 2002 issued a National Security Strategy that placed a priority on pre-emption, that is, on the employment of military force before an adversary had the opportunity to strike first. Similar grounds for taking pre-emptive action have since appeared in the later administrations and in more recent military operations.
In 2026 the United States and Israel carried out combined military strikes on Iran, prompting numerous questions as to whether their action had been legal. Has the use of force been approved by the UN Security Council? Does it satisfy the conditions for self-defence provided for in Article 51 of the UN Charter? International lawyers were in disagreement, though a great many held that the first use of force had been illegal under jus ad bellum, that is, the rules that determine when states may lawfully use force. This is to be distinguished from international humanitarian law (jus in bello), which regulates the way in which wars are conducted, regardless of whether the initial use of force was legal. Similar debates have arisen concerning the Russia-Ukraine war since 2022 and in relation to the conflicts in Sudan, Gaza and Lebanon.
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This raises questions about whether International Law still has any significance, since increasing aggression is endangering global stability. For many years, the world has had a certain level of peace, maintained by institutions that ensure order through international agreements designed to protect state sovereignty, respect human rights, and assist victims of disasters. However, the Global Peace Index report for 2026 indicates that the world is now considerably less peaceful than it was in 2008, the average level of peacefulness in countries having fallen by 6.5 per cent between 2008 and 2026.
The question of legality can be debated endlessly. The current practices of powerful nations in waging war are placing significant strain on the existing framework of International Law.
Because of unexpected wars, ordinary people on many continents have to suffer the human, humanitarian, and economic consequences. The Global Humanitarian Review 2026 states that 239 million people currently require urgent humanitarian aid and protection because of prolonged conflicts which have been more violent towards civilians and have lasted longer than at any time since the end of World War Two, together with a climate crisis that is worsening without any sign of stopping.
The price of energy has risen due to major disruptions to supply via the Strait of Hormuz caused by the ongoing conflict in the Middle East. Oil supplies through the Strait of Hormuz fell from 20 million barrels a day before the conflict to an average of 2.7 million barrels a day between March and May 2026. The International Energy Agency reported that by June 2026 the total losses suffered by countries in the Middle East had reached 1.3 billion barrels. These disruptions have caused a sharp rise in the cost of living, affecting the everyday lives of ordinary people.
What sorts of consequences follow from an international order that is fragmented and in which security is ever more based on military alliances and regional coalitions rather than on legally accepted rules?
Following the attacks of 9/11, there was a discussion among the states and scholars as to whether the framework of the Charter was still adequate. This discussion also involves distinguishing between anticipatory or pre-emptive self-defence, which is at times invoked in cases where an attack is seen as imminent, and preventive force, which is applied to a more remote or evolving threat. The latter is much more poorly supported by international law. New questions arose as a result of efforts to target individual terrorist leaders, to respond to non-state armed groups that operate from territory in other states, and to assess the threats posed by nuclear, chemical, or biological programmes regarding the concepts of imminence and necessity.
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Article 38(1) of the Statute of the International Court of Justice (ICJ) is generally regarded as the standard statement of the sources of international law and, when considering claims of self-defence, the Court has on numerous occasions regarded necessity and proportionality as essential requirements. In the case of Nicaragua, the Court dismissed the United States’ claim of collective self-defence on the facts of the case and once again stressed the importance of these restrictions on the legitimate use of force.
Similarly, when the Security Council was considering Israel’s attack on Iraq, it was pointed out that Israel had violated international law by launching its attack on the Osirak reactor in 1981. The Council strongly condemned the attack, pointing out that the months-long planning showed there had been no assertion of immediate necessity. The strike on Osirak constituted an obvious act of aggression.
On the other hand, the 2007 strike on Syria’s Al-Kibar facility attracted far less attention. Examples such as these demonstrate both the flexibility and the fragility of claims of anticipatory self-defence.
The aggressive actions are causing international law to change and are calling into question the basis of the present world order, since, for a long time, people have looked to giant, stable states for leadership.
The international legal system established after 1945 under the UN Charter and its various agreements remained significant not merely because it was powerful, but because the most powerful states sought to maintain global order. The creation of the WTO and the provision of support to bodies such as the International Court of Justice and the Bretton Woods institutions contributed to the world’s stability in economic, political and diplomatic respects. Even in cases where countries resorted to force, they frequently cited international legal concepts such as humanitarian intervention or the protection of civilians as justification.
The sudden changes do cast serious doubt on the world’s ability to regain the stability it had before. Should powerful countries cease supporting the institutions that had previously served their own interests, would the legal order survive? This vulnerability enables nations to adopt a more protective stance and to form coalitions for both security and economic reasons, resulting in a divided world lacking a definite global direction. This shows that International Law is weakening as states increasingly rely on political agreements and temporary alliances.
Fortunata Kitokesya is a lawyer and human rights expert. She can be reached at fortukito@gmail.com or on X as @fortunatak. The opinions expressed here are the writer’s own and do not necessarily reflect those of The Chanzo. If you are interested in publishing in this space, please contact our editors at editor@thechanzo.com.
