After claiming credit for killing Qassem Soleimani outside Baghdad International Airport, Donald Trump said that the world was now a “safer place.” This viewpoint was perhaps understandable, given Soleimani’s position as the commander of Iran’s Quds Force and his role in developing the Badr Organization in Iraq, Hezbollah in Lebanon and Syria, and the Houthi movement in Yemen, among numerous other fighting outfits around the world. At the heart of this sprawling violent network stood Soleimani. Not for nothing, Ayatollah Ali Khamenei called him “a living martyr of the revolution.”
But tonight Tehran claimed responsibility for launching missiles at U.S. bases in Iraq. And the record shows that removing leaders often leads to more chaotic violence—particularly against civilians.
In January 2016, Mexican marines captured Joaquín “El Chapo” Guzmán, the longtime head of the Sinaloa Cartel. Taking him off the streets made the gang bloodier than ever before. Not only did the amount of violence increase, but the target selection expanded to include innocent bystanders. A gang member who worked for a contemporary of El Chapo compared the type of cartel violence before and after the arrest: “If we wanted to kill you and you turned up with your wife and children, we couldn’t do anything. We couldn’t touch you. Now, they don’t give a damn … If they see you in a taco stand, they’ll come and shoot it up.”
More systematically, the economists Jason Lindo and María Padilla-Romo examined the effects of targeting high-ranking gang members on Mexican homicide rates from 2001 to 2010. This “kingpin strategy,” they found, increased homicides by 80 percent in the municipalities where the leaders had operated for at least one year.
Many militant groups have also become less restrained toward civilians after the death or imprisonment of senior figures. In 1954, the British launched Operation Anvil to stamp out the Mau Mau Uprising in Kenya. Capturing leaders around Nairobi initiated a period of uncoordinated, rudderless violence. South Africa’s African National Congress also became less tactically disciplined when its leadership was marginalized. In 1961, the ANC established an armed wing called Umkhonto we Sizwe, which came to be known as the MK. Leadership stressed the value of “properly controlled violence” to spare civilians. For three years, MK members complied by studiously avoiding terrorist attacks. After Nelson Mandela was sentenced to life imprisonment in 1964, however, young men in the ANC engaged in stone throwing, arson, looting, and brutal killings of civilians. The political scientist Gregory Houston observed that “the removal of experienced and respected leaders … created a leadership vacuum” that empowered undisciplined hotheads. When Filipino police assassinated the Abu Sayyaf founder, Abdurajak Abubakar Janjalani, in 1998, the group devolved into a movement of bandits that preyed on private citizens. When Nigerian police summarily executed the Boko Haram founder, Mohammed Yusuf, in 2009, the terrorist organization also turned ruthless against civilians. And the al-Qaeda–linked rebel group Ahrar al-Sham became even more radical after a 2014 attack on its headquarters, in the northwestern province of Idlib, Syria, took out its leadership.
The theory that removing leaders results in worse violence is supported by more than mere anecdote. In a couple of peer-reviewed studies, I’ve tested whether killing the leader of a militant group makes that group more tactically extreme. Across conflict zones from the Afghanistan-Pakistan to the Israel-Palestine theaters, my co-authors and I found that militant groups significantly increase their attacks against civilians after an operationally successful strike against their leadership. Vengeance is not the main driver, as the overall quantity of violence changes less than the quality does. So-called leadership decapitation does not elicit a paroxysm of violence, but makes it more indiscriminate against innocent civilians.
Leadership decapitation promotes terrorism by empowering subordinates with less restraint toward civilians. In empirical research, I’ve demonstrated that militant groups fare better politically when they direct their violence at military and other government targets rather than civilians. Unlike guerrilla attacks against government targets, terrorist attacks against civilian targets tend to reduce popular support, empower hard-liners, and, most important, lower the odds of government concessions. But lower-level members, compared with their superiors, are less likely to grasp that attacking civilians does not pay.
Senior leaders are the most likely to recognize the political perils of terrorism, because they tend to be among the oldest members of the group, have the greatest combat experience, and are relatively well read, helping them learn the risks of civilian carnage from their own experiences and those of other militant groups. For this reason, militant leaders throughout the world have exhibited learning behavior by eschewing over time indiscriminate violence against civilians, or by at least recognizing the strategic costs associated with that behavior. Because their replacements are less likely to have come to this realization, leadership decapitation is associated with more terrorism—not less—in the immediate aftermath of operationally successful targeted killings.
Of course, not all militant leaders appreciate the folly of terrorism or possess the organizational clout to prevent operatives from perpetrating it. To a large extent, the effects of targeted killing thus depend on the type of leader killed. As I predicted in October, the death of the Islamic State leader, Abu Bakr al-Baghdadi, did not increase the group’s terrorist attacks, because he had favored maximum carnage against civilians and exercised limited control over his subordinates, particularly “lone wolves” who simply declared their rhetorical allegiance to him. Leadership decapitation is most likely to increase terrorism when the leader understood the strategic value of tactical restraint toward civilians and imposed his targeting restraint on the rank and file. A salient example is the al-Aqsa Martyrs’ Brigades, which ramped up their terrorist attacks against Israeli civilians when their leadership was crushed during the Second Intifada.
Unlike Baghdadi, Soleimani recognized that mass-casualty violence can backfire. He understood the strategic value of keeping violent potential in reserve, especially against innocent people, unless explicitly instructed otherwise. This code of conduct is most evident in Hezbollah, the Iranian-proxy group whose rules of engagement proscribe ad hoc, mass-casualty attacks against Israeli civilians without approval from the top. This tactical restraint is also why Quds operatives have for years been hiding out in the Western Hemisphere and not blowing it up.
There are some positive signs that post-Soleimani Iranian proxies will continue to steer clear of civilians—at least American ones. In an interview with CNN, the Iranian senior military adviser Major General Hossein Dehghan affirmed that any Iranian retaliation will be restricted to U.S. military sites. The Hezbollah chief, Hassan Nasrallah, has likewise pledged restraint after the Soleimani killing: “It is the U.S. military that … must pay the price … We do not mean the American people. There are many U.S. civilians in our region—engineers, businessmen, journalists. We will not touch them. Touching any civilian anywhere in the world will only serve Trump’s policy.”
It looks like the U.S. is indeed already paying the price against predominantly military targets. As for restraint against civilians, calling for it is one thing; imposing it is another.