Editor’s Note: The killing of Qassem Soleimani is only the latest U.S. killing of enemies with terrorism links—a process that began with President George W. Bush, accelerated under President Barack Obama, and now has expanded to include state actors like Soleimani under President Donald Trump. Audrey Kurth Cronin of American University argues that these killings are a strategic mistake. The norms and laws against assassination protect strong powers like America more than weak actors like terrorist groups, and U.S. policies should not encourage this tactic. Daniel Byman

By Audrey Kurth Cronin, Lawfare: In killing Iranian Major General Qassem Soleimani, head of the Quds Force, with an MQ-9 Reaper drone, the United States openly targeted a senior official of a sovereign nation-state, carrying out a satisfying act of short-term revenge but undermining its long-term strategic interests. The United States had long been capable of killing him and, since at least 2007, had abundant reasons and numerous opportunities to do so. But Soleimani was a prominent senior Iranian leader, the United States was not at war with Iran, and past U.S. military and civilian decision-makers had declined to kill him. Legal arguments defending or critiquing the Jan. 3 killing take a narrow approach to the historic implications of the event: The hit on Soleimani demonstrates that we are in a destabilizing era of open assassination.

In the short term, the United States and its allies are better off without Soleimani. There is no doubt that he was a heinous enemy, plotting against American citizens just as he had done for years. There is no question that Soleimani had the blood of American soldiers on his hands—from during the U.S. military occupation of Iraq, the fight against the Islamic State, and the ongoing struggle over Iraq’s political future. There is no denying that the Iranians will miss his brilliant tactical maneuvering, which has been partly responsible for the dramatic growth of Iranian influence over the past two decades. Focusing on the advantages of his death, though, ignores the global history of assassinations; the current increase in their use; the new technologies that equalize the ability to target individuals; and the second-, third-, and fourth-order effects that will kill more Americans (and vital allies) in the future.

The terms “assassination” and “targeted killing” were once legally distinguishable. Until 2001, most people accepted a distinction between illegal assassinations of political figures during peacetime and lawful targeting of those who were an imminent threat in an armed conflict. Since 9/11, under the framework of global counterterrorism, these differences have become a matter of semantics. Any killing the president orders is now apparently lawful, at least under U.S. domestic law. However much we parse the finer legal points of the legitimacy of self-defense under Article II, or the Quds Force’s April 2019 designation as a Foreign Terrorist Organization, or the relevance or irrelevance of Executive Order 12333 banning assassinations, or even the unchecked growth of U.S. executive power, we are looking at the world through a straw. Whether or not it was technically a legal act, Soleimani’s killing will have a historic global influence.

To understand why this is so, we must start with the history of assassination. Assassination is one of the oldest tools of statecraft, a favorite tactic of weak states seeking leverage against strong powers. In “The Art of War” (5th century BCE), Ancient Chinese strategist Sun Zi wrote of assassination as a way to avoid costly warfare, using spies to gain “the identities of the defending commander, his retainers, counselors, gate officers, and sentries” so as to eliminate them. Indian statesman Kautilya also explained the benefits of assassinating enemy leaders to gain an advantage in “Arthashastra” (1st century BCE), his comprehensive guide to governance. The Iranians invented the term “assassins” in the 12th century. Rulers were commonly assassinated in 15th-century Italy: Niccolo Machiavelli spent much of The Prince discussing how to avoid it.

Banning assassination was not just the right thing to do; it was how modern nation-states consolidated their power. What the United States has done with the hit on Soleimani is undermine a pillar of support for stronger, status quo powers. With the development of international law in the 18th century, most states ruled out assassination precisely because it advantaged weaker states and nonstate actors. The Lieber Code, written during the American Civil War, expressly prohibited it. The Hague Conventions of 1899 and 1907 also banned assassination, and the Geneva Conventionsforbade killing anyone not directly involved in hostilities. Assassination as statecraft declined during this period for normative reasons but also because major powers feared retaliation and got better at physically protecting their territory. In the century that followed (and influenced by the devastating global consequences of the 1914 killing of Archduke Franz Ferdinand), the ban on assassinations was a practical way to prevent state leaders and senior officials from being killed and upending the international system. When major powers put certain people, such as political leaders and senior officials, off-limits for targeting by governments not engaged in a formal state of war, the act was a practical move that served their interests.

Of course, even with the ban in place, clandestine assassinations sometimes occurred. The Soviet Union called it “executive action” and killed former intelligence officers and emigres with ruthless efficiency. The United States tried to kill Fidel Castro and other senior leaders, as exposed in the 1975 Church Committee hearings that yielded Executive Orders 11905 and 12333. Iran engaged in a series of assassinations of prominent Iranians following the 1979 revolution, and Iranian proxies have routinely carried out killings in the decades since. Chile’s Pinochet regime was notorious for its killing of opposition officials under Operation Condor. The Israelis also have a strong tradition (they refer to it as either targeted killing or targeted prevention) that has included tracking and slaying operatives involved with the 1972 Munich Olympics massacre (Operation Wrath of God), targeting Palestinian leaders and bombmakers in the occupied territories, and killing Iranian nuclear scientists. Still, the fact that all of these actions were clandestine, often carried out by proxies, and officially denied reinforced a norm against state-sponsored assassination. That is now changing.

Assassinations are increasing because of evolutions in both state practice and available means. Newly accessible technologies, along with synthetic chemical and biological toxins, are lowering the threshold for states to carry them out openly, with impunity, across borders, at any time. The United States is not the only country with long-range armed drones like the Reaper that shot Hellfire missiles at Soleimani’s car as it drove away from the Baghdad airport. In 2013, Iran unveiled a Reaper-size large drone named the Fotros (or “Fallen Angel”), a mock-up that the Iranians claimed they had reverse-engineered from a U.S. Sentinel drone captured in 2011. Since then, the Iranians have greatly improved their drone capabilities, striking targets in northern Syria in 2016, flying a Shahed-129 over U.S. troops near the Al-Tanf military base in Syria in 2017, sending a Saegheh drone over Israeli airspace in 2018, and establishing their first Army Aviation school devoted to training unmanned aerial vehicle (UAV) pilots in June 2019. In killing Soleimani and then openly trumpeting that action, the United States has set a dangerous precedent that will be exploited by others with similar capabilities but different perspectives on legitimate targets.

The United States’s tactically brilliant but strategically dubious counterterrorism drone campaign has stopped dangerous operations and killed thousands of suspected terrorists, but it has also been a real-time global demonstration for every rogue state or underdog to justify using now-commonly-available UAVs in permissive airspace. The difference between killing terrorists like Osama bin Laden and Abu Bakr al-Baghdadi, on the one hand, and Major General Soleimani, on the other, is that Soleimani was a senior official in the hierarchy of a sovereign nation-state.

Assassinations are occurring even on the territories of allies with strong police and military institutions, such as the United Kingdom, or in well-monitored public places like airports, as in Malaysia. Russian hitmen poisoned former Federal Security Service (FSB) officer Alexander Litvinenko with polonium-210 in London in 2006. North Korea agents used two duped female proxies to assassinate Kim Jong-nam (half-brother of Kim Jong-un) at Kuala Lumpur airport with VX nerve agent in 2017. Russia attempted to assassinate Sergei Skripal and his daughter Yulia in Salisbury, England, with the Novichok nerve agent A-234 in March 2018. Three months later, Vienna-based Iranian diplomat Assadollah Assadi tried to bomb a meeting of the National Council of Resistance of Iran in Paris using 500 grams of the explosive TATP. Only last month, Russia conducted a hit in Berlin on a former Chechen rebel fighter, according to German authorities. Russia was slapped with more sanctions and North Korea landed back on the United States’s list of state sponsors of terrorism, but neither response had much effect. States are suffering few, if any, political or legal consequences for these actions.

In addition to facing few penalties for conducting assassinations, the tactic is becoming easier to employ. Clusters of newly accessible technologies—including cyber operations, facial recognition technology, smartphones, quadcopters, autonomous systems and small satellites—are lowering the threshold for lethal reach by minor powers and nonstate actors. And it is becoming more challenging to isolate U.S. and allied citizens and territory from physical threat: For example, massive data breacheshave exposed the personal information of a wide range of senior American experts, military and civilian. The result is an intersection of greater technological capability matched by enhanced U.S. and allied vulnerability.

The growing availability of new lethal technology along with a deteriorating state norm against assassination benefits weaker states and nonstate proxies, such as Iran and Hezbollah, in relation to stronger states such as the United States, whatever its awesome traditional military capabilities. The Iranian response to the killing of Soleimani will not be confined to missile attacks on U.S. bases in Iraq but will also threaten U.S. military members and civilians in soft targets and unexpected places throughout the world. That will be globally destabilizing in the coming months and years, and it does not serve U.S. strategic interests.

We are in a dangerous period: Revenge is an ungovernable impulse that easily spirals out of control. Going forward, the United States must take the lead in sharply distinguishing itself from rogue actors who engage in treacherous acts of assassination. First, the president must stop personalizing this killing. The actions of a nation-state have greater significance than those of any individual, and the language of personal vendetta lands us back in the 15th century. Second, the United States must urgently restore a serious interagency process staffed by experts who assess the strategic effects of such killings—especially those that may be perceived as an assassination and casus belli by the victim’s government. This is not a novel suggestion, but it’s more urgent than ever. Third, the United States must recognize that it has lost its monopoly on precision targeting. Democratized digital technologies have enabled weaker states and nonstate actors to more effectively target the United States and its personnel and facilities abroad in ways that were once exclusive to Washington’s arsenal. U.S. policymakers must resist the temptation to use their technological and military prowess to target senior government officials, remembering who is watching and learning from what they do.

First published in Lawfare. Cartoon by Stephane Peray. 

Audrey Kurth Cronin is director of the Center for Security, Innovation, and New Technology at American University and the author of “Power to the People: How Open Technological Innovation Is Arming Tomorrow’s Terrorists,” just released by Oxford University Press.