The Assassination That Changed War's Rules

Saturday's Israeli bombing that killed Iran's Supreme Leader, Ayatollah Ali Khamenei, didn't just eliminate one of the past half-century's most influential global figures—it shattered a taboo that has held for nearly 50 years. We're witnessing something almost unprecedented in modern warfare: the successful assassination of an enemy head of state by a foreign military.

To find a comparable operation, you'd have to go back to the same year as the Iranian revolution itself. The closest precedent may be the KGB's assassination of Afghan Communist leader Hafizullah Amin in 1979—the opening act of the Soviet invasion that triggered a bloody decade-long war.

While the strike that killed Khamenei likely doesn't violate international law, it represents a dramatic escalation with enormous potential for unintended consequences. If this becomes the new normal, the rules of global conflict may never be the same.

When Leaders Led From the Front

In centuries past, rulers like Persia's Cyrus the Great and England's Richard III personally led troops into battle and often paid the ultimate price. But modern leaders almost universally stay well back from front lines or, when under threat, retreat to heavily fortified bunkers. They leave the killing and dying to others.

That's what made Khamenei's presence at a meeting with senior officials in his well-known Tehran compound so surprising, especially given abundant signs that airstrikes were imminent. According to The New York Times, he told his inner circle he accepted the risk because he didn't want to appear to be hiding.

The rarity of successful "decapitation" operations hasn't been for lack of trying. The 2003 "Shock and Awe" campaign deliberately targeted Saddam Hussein, who had orchestrated a plot to assassinate former President George H.W. Bush in 1993. The Reagan administration unsuccessfully bombed Libyan leader Muammar al-Qaddafi's compounds in 1986. NATO targeted Qaddafi's compounds again during the 2011 intervention in Libya.

Ukrainian President Volodymyr Zelenskyy has reportedly survived multiple assassination attempts since Russia's 2022 invasion. But none of these previous targets were heads of internationally recognized states who were successfully eliminated.

The Legal Gray Zone

Is killing an enemy head of state in wartime legal? Mostly, yes. A civilian head of state who commands a country's armed forces—as Iran's Supreme Leader does—is considered a legitimate military target under international law. It's not fundamentally different from the US military shooting down Japanese Admiral Isoroku Yamamoto, the Pearl Harbor mastermind, in 1943, or Ukraine targeting Russian generals today.

International law prohibits killing military or government personnel through "treachery"—breaches of trust like feigning surrender or impersonating UN officials. But given Trump's repeated warnings about impending airstrikes, that would be a tough claim for Iran to make.

US law, codified in executive orders by Gerald Ford and Ronald Reagan, prohibits government employees from engaging in assassination. This prohibition emerged after congressional investigations revealed the CIA's role in killing leaders like the Democratic Republic of Congo's Patrice Lumumba, South Vietnam's Ngo Dinh Diem, and Chile's Salvador Allende, plus plots against Cuba's Fidel Castro.

But crucially, the US wasn't at war with those leaders' countries when it helped kill them. "Assassination usually has political motives and occurs outside the context of armed conflict," explains Michael Schmitt, professor of international law at the University of Reading. "Once bombs begin dropping, you shift to the law of armed conflict to determine who may be attacked."

Why Leaders Usually Avoid the Nuclear Option

The sparing use of assassination as military strategy probably has more to do with custom and political calculation than legal constraints.

For starters, it's harder to negotiate a quick end to war if you've killed the person you'd want to negotiate with. Killing a leader can also make your adversary fight harder rather than surrender.

During World War II, British intelligence developed several plots to kill Adolf Hitler, but some officials worried about turning him into a martyr. Before the first Gulf War, Defense Secretary Dick Cheney fired Air Force Chief of Staff Michael Dugan for telling reporters about plans to "decapitate" Iraqi leadership by targeting Saddam Hussein and his family. (The US did ultimately strike Saddam's compounds—the problem was Dugan talking about it publicly.)

In the Khamenei case, the killing signals that Israel, with US support, is more interested in destroying this regime than cutting deals with it. Though the CIA reportedly provided intelligence that enabled the strike, officials including Secretary of State Marco Rubio and Defense Secretary Pete Hegseth have emphasized this was an Israeli operation—the US isn't directly targeting Iranian leaders.

"To assassinate a head of state who's also a religious figure, even under Trump, the United States would prefer that Israel do it," says Shira Efron, a former Israeli government adviser now at the RAND Corporation.

Trump himself hasn't quite stayed on script. "I got him before he got me," he told ABC News, referring to several Iran-backed assassination plots against him. His comment illustrates another reason leaders avoid normalizing assassination: they'd prefer it not happen to them.

The Troubling New Frontier

Khamenei's death may be the first of its kind in nearly half a century, but it could signal more to come. We're living in a world where wars between sovereign states are becoming more common after years of decline. Data suggests political assassinations are also rising—a danger Trump knows all too well.

Technological advances in precision bombing and satellites have made targeting individuals at great distances far easier. Drones, which can be manufactured cheaply and deployed easily by less-advanced militaries or proxy forces, add a new deadly dimension to assassination capabilities.

The Allies could massively bomb Berlin but had little hope of knowing exactly where to drop a bomb to kill Hitler. Today, that precision is reality. The reported use of Anthropic's Claude AI system in the Khamenei strike suggests artificial intelligence may soon make such operations even easier.