The assassination of Iran’s Supreme Leader Ayatollah Ali Khamenei by Israel, with US backing, has opened a complex legal debate over whether the killing of a sitting head of state at the outset of war can be justified under international or American law, according to an in-depth analysis published by The New York Times.
The newspaper notes that while critics have already challenged the broader US-Israeli military campaign against Iran as lacking congressional or United Nations Security Council approval, the targeted killing of Khamenei presents a separate and far more intricate legal question -- one that has few modern precedents.
It is exceedingly rare for one country to deliberately and openly assassinate the leader of another sovereign state, even during armed conflict.
The closest historical comparison, the Times observes, dates back to March 2003, when the George W Bush administration attempted to kill Iraqi leader Saddam Hussein on the eve of the Iraq War.
Although that war had congressional authorization, the strike failed to hit its target.
According to the Times, the joint operation led by US President Donald Trump and Israeli Prime Minister Benjamin Netanyahu began on February 28 with a surprise assault on Iran’s leadership.
Ayatollah Khamenei, who had ruled Iran for nearly four decades, was killed in the strike.
US officials told the newspaper that the CIA tracked Khamenei’s movements and provided intelligence on his location to Israel, which ultimately carried out the attack.
The plan, the report said, had been accelerated to seize what officials described as a narrow operational opportunity.
The White House, when asked by the Times to provide a detailed legal justification, said only that Trump had exercised his authority as commander in chief “to protect US forces and bases in the region.”
The statement referenced Iran’s past actions but did not directly address the legality of targeting Khamenei.
A central issue highlighted by the Times is Khamenei’s dual role.
Though a cleric and not a uniformed officer, he served as Iran’s commander in chief.
Under the laws of armed conflict, military commanders are legitimate targets.
Civilian officials without military responsibilities are generally not, unless they directly participate in hostilities.
Legal scholars interviewed by the newspaper noted that a civilian head of state who exercises operational control over armed forces occupies a grey area.
Such a figure could arguably be treated as a lawful military objective in an active conflict.
However, the timing of the strike complicates that argument.
If the killing marked the beginning of hostilities, the question becomes whether an armed conflict legally existed at that moment.
Killing a foreign leader in peacetime, absent an imminent armed attack, would generally constitute an unlawful use of force under international law.
Under the UN Charter, to which the United States is a party, a state may not use force against another state’s territory without Security Council authorization or a valid claim of self-defense.
Even if an individual is deemed a legitimate military target, the broader use of force must itself comply with the Charter.
The Trump administration has relied on the concept of an “imminent threat” to justify its actions.
In a televised address, Trump said the operation aimed to eliminate an imminent danger posed by the Iranian regime.
He referred to concerns about nuclear weapons and long-range missile development but did not present evidence of a pending armed attack.
Secretary of State and National Security Adviser Marco Rubio later said there had been “certainly an imminent threat,” arguing that US intelligence believed Israel was preparing to strike Iran and that Tehran would retaliate against US bases.
The United States, he suggested, joined the operation pre-emptively.
Legal analysts cited by the Times note that international law traditionally requires a clear and immediate danger for anticipatory self-defense to be lawful.
A broad or preventive interpretation of “imminence” risks stretching the concept beyond established norms.
The Times also examined whether the war itself was legally initiated under US law.
The Constitution grants Congress the authority to declare war, yet presidents since World War II have frequently launched limited military actions without formal declarations.
Executive branch lawyers have argued that if the “nature, scope and duration” of an operation fall short of a full-scale war, the president may act unilaterally.
However, major conflicts such as the 1991 Gulf War and the 2003 Iraq War were preceded by congressional authorization.
If the current campaign against Iran expands significantly, the paper suggests, it could become the largest unilateral military action undertaken without explicit congressional approval since the passage of the 1973 War Powers Resolution.
Another dimension involves Executive Order 12333, which prohibits US government personnel from engaging in or conspiring to commit assassination.
The order does not define “assassination,” and successive administrations have interpreted it as not applying to lawful military actions or self-defense strikes.
In 2020, Trump ordered the killing of Iranian General Qassem Soleimani in Iraq.
A Justice Department memorandum defending that strike did not directly address the assassination ban but argued that Soleimani posed an ongoing threat to US forces.
The Times notes that targeting a sovereign head of state is categorically different from targeting a non-state militant leader.
If the killing of Khamenei were deemed unlawful under international law, any state that knowingly assisted in the operation could share responsibility under principles of state accountability.
The newspaper concludes that the assassination of a sitting head of state at the outset of war presents an unprecedented convergence of domestic and international legal issues.
Whether justified as self-defense or condemned as unlawful aggression, the act is likely to shape future interpretations of executive power and the limits of force.
As the conflict intensifies and diplomatic efforts remain stalled, the legal debate surrounding the killing of Ayatollah Khamenei underscores the broader question at the heart of the crisis: not only whether war was necessary, but whether it was lawful.
