Table of Contents
Greg Bouwer
IINZ
A state faces an adversary whose leadership has spent decades declaring its intention to eliminate it. That adversary is developing long-range missiles and nuclear technologies while financing armed groups that repeatedly attack civilians across the region. Those attacks are carried out through proxy organisations deliberately structured to blur legal responsibility.
International law’s answer is simple: wait.
Wait until the attack comes, or until the threat becomes unmistakably imminent. Only then does the right of self-defence clearly arise.
That tension sits at the heart of the current debate in New Zealand over Israeli and American strikes against Iran. Critics often invoke the “rules-based international order”, arguing that any military action without clear legal justification undermines the system that protects small states.
But the debate raises a deeper question.
What happens when the rules themselves no longer match the realities they are meant to govern?
The charter was designed to restrain aggressors, not protect them
The modern legal framework regulating the use of force was created after the second world war. The authors of the United Nations Charter sought to prevent aggressive wars like those that had devastated Europe.
Article 2(4) prohibits the use of force between states. Article 51 recognises a limited exception: the inherent right of self-defence when an armed attack occurs.
This structure made sense in the world of 1945. Wars were fought primarily between states, armies mobilised visibly, and aggression was unmistakable.
The threats confronting states today look very different.
Since the Islamic Revolution of 1979, Iranian leaders have repeatedly described Israel as an illegitimate entity that should disappear. At the same time, Iran has pursued advanced missile capabilities and nuclear technologies while supporting armed groups hostile to Israel across the region.
Whether one accepts Israel’s assessment of the immediacy of the threat or not, the strategic dilemma is clear. If international law is interpreted in a way that prevents a state from responding to long-term existential threats, the law risks undermining the purpose for which it was designed.
Proxy warfare exploits a structural weakness in the law
Iran’s regional strategy relies heavily on proxy organisations, including Hezbollah in Lebanon, Hamas and Palestinian Islamic Jihad in Gaza, and allied militias operating in Iraq, Syria, and Yemen.
These groups have launched thousands of rockets at Israeli cities and conducted attacks on civilians. Yet because these organisations are not formally Iranian armed forces, the legal framework governing the use of force often treats Iran’s responsibility as indirect.
This ambiguity is not accidental. Proxy warfare exploits a structural weakness in international law.
The UN Charter was written primarily to regulate conflict between states. But modern conflict increasingly occurs through networks of non-state actors funded, trained, and armed by states seeking plausible deniability.
If international law cannot adequately attribute responsibility in such cases, the result is a system that constrains conventional military responses while leaving proxy warfare relatively unchecked.
A credible rules-based order must therefore strengthen doctrines of state responsibility for non-state actors, recognising that states directing or sustaining proxy attacks bear responsibility for the consequences.
Nuclear weapons change the meaning of imminence
International law has long recognised a limited right of anticipatory self-defence. The classic formulation comes from the 19th-century Caroline affair, which held that self-defence may be justified when the necessity is “instant, overwhelming, leaving no choice of means and no moment for deliberation”.
This standard assumes that threats develop gradually and that defensive action can be delayed without permanently losing the ability to respond.
Nuclear weapons fundamentally alter that assumption.
Once a hostile regime acquires nuclear capability, the strategic landscape changes in ways that cannot easily be reversed. The margin for error disappears.
In that context, insisting that states wait for unmistakable imminence before acting may not represent caution. It may represent the permanent loss of any effective defensive option.
The Caroline test made sense in an era of sailing ships and muskets. Its application to nuclear proliferation and proxy terror groups is a different matter entirely.
When the law got it wrong
Israel’s 1981 strike on Iraq’s Osirak nuclear reactor illustrates the tension.
At the time, the attack was universally condemned. The United Nations Security Council unanimously adopted Resolution 487 declaring the strike illegal.
Yet after the Gulf War revealed the scale of Saddam Hussein’s nuclear ambitions, many analysts reassessed the episode. Had Iraq succeeded in acquiring nuclear weapons in the 1980s, the strategic consequences for the Middle East could have been severe.
The international community’s legal judgment had been confident and unanimous. In retrospect, it may also have been dangerously wrong.
That does not mean pre-emptive strikes should be treated casually. But it does demonstrate that the current legal framework can produce verdicts that fail to account for the realities of emerging threats.
The hardest question: who decides?
Critics of pre-emptive action raise a powerful objection. If states can attack whenever they claim an existential threat, the prohibition on aggressive war collapses. Every aggressor in history has claimed self-defence.
This concern is valid.
But the alternative often proposed – requiring authorisation from the United Nations Security Council – is not a neutral safeguard. It is a structural guarantee of paralysis in cases involving major geopolitical interests, where veto powers can block any action.
The ‘who decides?’ problem therefore has no perfect solution.
In practice, the international system relies on a combination of state judgment, public scrutiny, and retrospective accountability to evaluate claims of self-defence. States that misjudge the legitimacy of their actions face real costs – diplomatic isolation, economic pressure, loss of coalition support, and damage to their credibility. These consequences do not eliminate abuse, but they do constrain behaviour in ways that purely formal rules cannot always achieve.
Why this matters for New Zealand
For New Zealand, these issues are not abstract.
Our security ultimately depends on a functioning international order. But that system derives its legitimacy from reciprocity: states comply with rules because they believe others will do the same.
When a legal framework appears unable to address proxy warfare, nuclear proliferation, or the systematic bad faith of states that exploit its gaps, confidence in the system erodes.
New Zealand can play a constructive role in addressing these tensions. Within multilateral forums, Wellington has traditionally been a strong advocate for international law. That position places it well to contribute to the ongoing debate about how the legal framework governing self-defence should adapt to modern threats – including clearer standards for state responsibility in proxy warfare and more realistic interpretations of anticipatory self-defence in the nuclear age.
That debate cannot wait for the system to fracture before it begins. The pressure is already visible in conflicts where existing legal categories struggle to describe the reality on the ground – and where states are already making decisions the framework cannot adequately guide.
International law cannot resolve every security dilemma. But it must remain credible to the states whose survival may depend on it.
That credibility rests on a recognition that the right of national survival ultimately precedes any legal framework. International law does not create states: it presupposes their existence.
If powerful states conclude that the rules offer them no viable path to protect themselves, they will eventually abandon them.
And when the system collapses under that pressure, it will not be replaced by a more just order – only by a more dangerous one.
This article was originally published by the Israel Institute of New Zealand.
