For the first time since the landmark 2015 Iran nuclear agreement was abandoned, the spectre of direct confrontation between the United States and the Islamic Republic of Iran looms as a tangible and immediate geopolitical risk. What began as a series of mass anti-government protests sparked by a deepening economic crisis and a collapsing currency has morphed into a Western political crisis, diplomatic brinkmanship, and the very real possibility of military intervention, a turn of events that demands rigorous legal and international analysis.
At the heart of this rapidly shifting crisis is the rhetoric emanating from the White House. In a sequence of increasingly stark statements, President Donald Trump, speaking to reporters aboard Air Force One, has suggested that Iran’s leaders have reached out to the United States seeking negotiations, while at the same time warning that the U.S. might act militarily before any negotiated meeting takes place. “A meeting is being set up… they want to negotiate…we may have to act before a meeting,” he said, coupling the claim of diplomatic outreach with threats of force.
This duality, diplomacy publicly acknowledged, coercive military pressure implied, raises profound legal questions about the legitimacy and probable consequences of U.S. action under international law.
The protests that have spread through more than 180 cities across Iran can be traced back to late December 2025, when economic grievances including skyrocketing inflation, food insecurity, and the collapsing rial, ignited a broader movement demanding political reform. Human rights monitoring groups place the reported death toll in the hundreds, possibly exceeding 600, with more than 10,000 arrests as security forces crack down often with lethal force.
Under the core tenets of public international law, mass civilian casualties alone do not provide a lawful basis for the use of force by another state. The United Nations Charter, Article 2(4), expressly prohibits the threat or use of force against the territorial integrity or political independence of any state, absent explicit Security Council authorisation or a clearly established right of self defence under Article 51. A pro-democracy movement, however tragic in its mortality figures, remains an internal matter under the domestic jurisdiction of the Iranian state unless there is clear evidence of an armed attack against another state and there is none at present.
Trump’s initial rhetoric on 2 January: “locked and loaded and ready to go”, invoked a form of extraterritorial humanitarian intervention that the international legal order explicitly forbids. Experts have debated the legality of humanitarian intervention without Security Council approval, and while some argue for its moral necessity in extreme cases of mass atrocities, the prevailing legal consensus is that such action remains outside the framework of permissible use of force. It is not codified in the Charter and remains highly contested.
The administration’s subsequent statements expanded the range of possible responses beyond kinetic military action. White House Press Secretary Karoline Leavitt reiterated that diplomacy is “always the first option” even as military options including limited strikes, economic sanctions and cyber operations remain on the table. The reported consideration of new tariffs of 25 per cent on any country that conducts business with Iran underscores how economic tools are being incorporated into a broader coercive strategy.
From a legal standpoint, however, the imposition of tariffs on third party states that trade with Iran has its own complications under international trade law. Under the General Agreement on Tariffs and Trade (GATT) Article I and Article II, discriminatory tariffs are generally prohibited unless justified under exceptions such as national security (GATT Article XXI). The breadth of the announced 25 per cent tariff, targeting potentially dozens of countries, raises serious questions about whether it can legitimately be classified as a national security measure, or whether it constitutes an extraterritorial sanction regime that could invite disputes at the World Trade Organization.
Iran’s official responses add considerable legal and geopolitical complexity. Iranian Foreign Minister Abbas Araghchi stated that Tehran is “prepared for war” but also open to negotiations, provided they are “fair and honourable,” based on mutual respect and without coercive diktat. Tehran insists the situation is under control, framing the protests internally and denouncing perceived external interference, particularly from Washington and its allies.
This posture underscores a core legal reality: Iran remains a sovereign state with all rights under the UN Charter. Its own threats to treat U.S. military bases and Israeli assets as legitimate military targets if attacked are themselves not mere rhetoric; under the laws of war, a state under attack has the right to self defence (Article 51 of the Charter). Any U.S. action against Iranian territory, whether air strikes against alleged regime sites or sabotage of infrastructure, would constitute an “armed attack” against a sovereign state, thereby triggering Iran’s legal right to defend itself.
Moreover, the invocation of regime violence against protesters as a justification for U.S. intervention replicates a legal argument that has been repeatedly challenged in international affairs namely that gross human rights abuses by a government authorise external military intervention. There is no clear doctrine in international law that permits one state to intervene militarily in another state solely on the basis of internal human rights abuses, absent Security Council authorisation. The “Responsibility to Protect” doctrine, developed in the early twenty first century, remains a political concept rather than a legally binding basis for military action without Council approval.
Trump’s suggestion that the U.S. might act “before a meeting” even as negotiations are discussed sits awkwardly with longstanding legal norms. The Israeli Supreme Court and various international jurisprudence have stressed that negotiations cannot be simultaneously pursued and preemptively undermined by threats of force. A threatened strike intended to coerce Iran on the basis of internal unrest would likely be interpreted, by Tehran and many members of the international community, as an unlawful use of force.
Already, the Iranian parliament speaker, Mohammad Baqer Qalibaf, has issued stark warnings that American and Israeli sites would be considered legitimate retaliatory targets in the event of U.S. military action. Such promises increase the risk of escalation, not de-escalation. They reflect more than political posturing; they signal a credible claim that any U.S. military operation could transform into wider regional conflict, involving not just Tehran but allied non-state actors and state proxies across the Middle East.
International reaction has been mixed but deeply concerned. The United Nations Secretary General has called for restraint and emphasised the primacy of diplomatic solutions. Europe’s political leadership has urged respect for Iran’s sovereignty and warned against unilateral military options. Russia and China have both criticised potential U.S. action as destabilising, framing it as interference in internal affairs. This reflects not just geopolitical alignment but fundamental disagreements about the interpretation of legal norms governing state conduct.
The timing of Trump’s statements matters. They follow a period of sustained economic sanctions and dramatic U.S. strikes against Iranian nuclear facilities, as well as heightened rhetoric linking Tehran’s missile programs to regional instability. The legal environment has already been strained by the collapse of the Joint Comprehensive Plan of Action and the unilateral imposition of “maximum pressure” sanctions regimes. These actions have historically been justified under national security exceptions, but critics argue that they undermine the stability of the non-proliferation regime and erode multilateral legal frameworks.
It is therefore not merely a matter of political grandstanding to suggest that a U.S. military strike against Iran could violate fundamental principles of the UN Charter and customary international law. The risk of regional escalation particularly if Iranian retaliatory measures involve attacks on U.S. or allied forces, or disruption of critical energy infrastructure, cannot be overstated.
This is a crisis that intersects with multiple legal domains: the law of armed conflict, the prohibition on the use of force, international trade law, and human rights protections. Each domain carries its own jurisprudence and institutional mechanisms, from the International Court of Justice to the World Trade Organization. Yet in practice, enforcement remains fragmented.
For the United States and Iran, the present moment demands an approach grounded in respect for legal norms rather than the theatrics of deterrence by threat. Genuine negotiations, conducted through intermediaries such as Oman or under UN auspices, offer the only feasible path to de-escalation that remains consistent with international law.
Absent such restraint, the legal and geopolitical consequences of miscalculation could be catastrophic, not only for Iran and the United States but for the broader international order that has, however imperfectly, governed interstate relations since 1945.