When International Law Can't Keep Up With Existential Threats

Asking whether Israel's actions violate international law is not the right question

Many pundits are arguing that the joint Israeli-US airstrikes against Iran were illegal under international law — that no imminent threat existed to justify the use of force. They have a point, as far as the existing legal framework goes. But that framework is precisely the problem.

The UN Charter, the Geneva Conventions, and customary international law were built around a specific model of aggression: armies massing at borders, attacks that are sudden and identifiable, threats that cross a clear threshold of imminence. Under this model, a state may act in self-defense only when an attack is underway or unmistakably about to begin.

That model made sense for the world it was designed for.

Iran’s threat to Israel — and to regional stability more broadly — does not fit that model. It has been built slowly, over decades, through proxy terror networks, ballistic missile development, nuclear weapons research, and relentless incitement calling for the destruction of a UN member state. Each individual step, examined in isolation, stays just below the threshold that would legally justify a military response. The aggression is incremental.

International law has no adequate answer for a state that sponsors proxy forces attacking its neighbors, lies systematically to international inspectors, arms terrorist organizations targeting civilians worldwide, and builds toward a weapons capability — all while the clock runs. The default legal answer is to wait. Wait for formal imminence. Wait for undeniable proof. Wait until the threat is so advanced it can no longer be stopped.

For most countries, waiting is a viable strategy. For a small state that its adversary has pledged to eliminate, it is a gamble with national survival.

There is a second dimension that international law fails to capture: deterrence logic. Israel now has a demonstrated record of making clear that anyone who plans or funds a major attack will eventually face consequences. That credibility is itself a form of war prevention. It changes the calculation for future terror sponsors. After the Munich Olympics massacre, and after October 7, Israel has made clear that every party involved will pay the price eventually. Iran is Hamas’ main financial and military sponsor. The only disincentive fo rthat is assassination-level response, to deter attacks in the future.

International law offers no framework for evaluating whether such deterrence reduces the overall probability of mass-casualty conflict. It only evaluates the legality of the discrete action. But a nation like Israel cannot afford to experiment. Deterrence is a major weapon it has and it seems logical that, for example, after eliminating Hezbollah’s previous leaders, the current leader will be a lot more cautious before deciding to attack.

The argument that survival justifies action beyond codified legal thresholds is not new, and it has been abused. Preventive war is one of the most dangerous doctrines in international relations. Any state invoking existential exception must meet a high evidentiary burden: the threat must be sustained, documented, and severe; alternatives must have been exhausted; and proportionality must be maintained and accounted for. This doctrine cannot become a blank check for any country to act aggressively claim long-term self defense. But we are talking about legitimate existential fears, not excuses for starting wars. International law cannot distinguish between the two, but that doesn’t mean a nation under real threat must wait until its enemies gain enough strength to destroy it.

In Iran’s case, the evidentiary record is extensive and public. Iran’s proxies have deliberately targeted civilians across multiple continents. Iran’s own missile strikes in the past 24 hours — aimed at hotels in Dubai and a residential building in Bahrain, far from any military installation — confirm that civilian targeting is intentional. The pattern is unambiguous. The burden, in this instance, is met.

Iran claims it only strikes military targets. The events of this weekend have made that claim untenable.

There is an irony in all of this. Israel is regularly accused of violating international law regardless of how carefully it adheres to it. That persistent bad faith has a perverse consequence: it reduces the reputational cost of acting outside the legal framework in genuine cases of necessity. When the rules are applied asymmetrically they lose their moral authority. Israel did not create that asymmetry. It has simply learned to operate within it.

I’m not saying that international law should be discarded. It is that the current framework has a structural gap. It wasn’t designed to address slow-motion existential aggression, the deliberate, patient accumulation of threat below the imminence threshold, sustained over decades. Forcing threatened states to absorb that accumulation until it crosses a formal legal line doesn’t prevent war: it increases the probability of a far more catastrophic one.

If the international system cannot address this class of threat, it must evolve. The imminence doctrine needs a framework for sustained, documented, existential aggression, one that sets high standards for evidence and proportionality, but does not demand that a small state wait for the blow it may not survive.

International law must evolve to take its own stated purpose seriously.