On February 28 the United States and Israel carried out what the White House described as a pre-emptive military strike against targets in Iran, a move Washington says was intended to head off an imminent threat. The administration framed the action as necessary to deter a range of dangers it attributes to Tehran, from support for militant groups to missile programmes and suspected nuclear ambitions.
White House press secretary Leavitt told reporters the decision was based on the “cumulative effect” of what the president judged to be an urgent and direct threat from Iran, listing Tehran’s backing for groups the US calls terrorist organisations, its ballistic missile activities, and alleged efforts to acquire nuclear weapons. Those claims were presented as the factual basis for a judgment that an attack by Iran was imminent and that force was therefore warranted.
Several international law scholars have pushed back sharply on that rationale. Mary Ellen O’Connell, a professor of law at the University of Notre Dame, said the strike has “no legal justification” under the United Nations Charter, which limits the lawful use of force to Security Council authorisation or narrow self‑defence against an actual or imminent armed attack. O’Connell emphasised that international law requires states to seek peaceful means — negotiation, mediation or international organisation involvement — and that vague references to future dangers fall short of the evidentiary threshold.
The administration’s public account has been inconsistent. Secretary of State Rubio earlier argued the US struck because it feared Israel would itself attack Iran and that Washington could become a target of Iranian retaliation; the White House said this made a preemptive move necessary. President Trump, however, denied that Israel had been the proximate reason, insisting instead that US intelligence pointed to an incoming Iranian assault. Brian Finucane, a former State Department legal adviser, said both lines of argument are problematic and argued that Washington’s leverage over Israel might have been used to prevent an Israeli strike without resorting to US force.
The dispute maps onto a longer legal and diplomatic debate over anticipatory self‑defence. The UN Charter’s Article 51 recognises the inherent right of self‑defence if an armed attack occurs, but it does not clearly authorise preventive attacks; customary formulations derived from the 19th‑century Caroline doctrine demand that any pre‑emptive action satisfy strict tests of necessity and immediacy. Legal critics say the White House account has not supplied the sort of concrete, time‑sensitive evidence that would meet that standard.
Beyond the legal niceties, the episode has immediate geopolitical consequences. If accepted as lawful, a broad reading of imminence could lower the bar for the use of force and encourage states to strike on the basis of ambiguous intelligence, increasing the risk of miscalculation and wider regional escalation. For Washington, the credibility costs are asymmetric: allies and adversaries alike will judge whether the administration’s claim‑making can be relied on, while international institutions may find their authority undermined if powerful states bypass them.
The coming days are likely to see diplomatic pressure for transparency and for scrutiny at the United Nations, where Iran and its partners could press legal and political challenges. How the Biden administration—if still in office—or other Western capitals respond, whether by publishing evidence, seeking Security Council backing, or pursuing other forms of restraint, will shape whether this episode hardens a new, looser norm on pre‑emptive force or stimulates a reassertion of legal constraints on the use of armed force.