Did Soleimani Pose an Imminent Threat?

As a justification for the killing of Iranian commander Qasem Soleimani in Iraq, the Trump administration has argued that he presented an “imminent threat.” Why is this label important?

There are two big legal debates going on here: whether the strike against Soleimani was justified under international law, and whether it was authorized under domestic law. Let me start with three preliminary points that apply to both. First, the facts are complicated, because there are multiple conflicts and types of military operations going on in Iraq that involve Iran, including against the self-proclaimed Islamic State and against Iran-backed militias. Second, it remains unknown what exactly the intelligence showed at the time, and that could be important to resolving these questions. And third, Donald J. Trump’s administration has offered only vague and shifting rationales, and it has used the word “imminent” loosely.

With regard to international law, states may use force in self-defense against armed attacks. That is generally understood to include defending against imminent attacks, which traditionally has meant attacks that are about to occur. By using this term initially to describe the Soleimani strike, the Trump administration led many people to believe that this was its international law argument: that Iran, and specifically Soleimani, was about to launch a major attack, and that killing him was necessary to prevent it.

What is the legal debate over “imminence?”

Traditionally, self-defense has included the right to prevent “imminent” attacks, meaning those that are just about to occur. This rule on “imminence” struck a sensible balance: states shouldn’t be allowed to use force based on mere speculation about future threats, but they also shouldn’t have to wait to suffer the first blow if an enemy is about to strike.

Recent U.S. administrations have wrestled with how to apply this rule in the contexts of weapons of mass destruction and terrorism, when it may be especially difficult to know where and when an attack will occur, and when the consequences of waiting could be catastrophic. Now, the Trump administration seems to be using the term very loosely, without explaining what it means.  

Turning to domestic law, modern presidents have asserted very broad constitutional authority to use force, especially in defense of American troops. The Trump administration is drawing on that past practice for at least part of its justification. If Iran, and especially Soleimani personally, was preparing an imminent attack, this would further bolster the claim that Trump had wide latitude to launch military strikes. However, the law in this area is highly contested, and because courts rarely get involved, it often boils down to a political contest between the executive branch and Congress.

If Soleimani did not pose an imminent threat, are there other credible justifications the administration could use for this strike?

Yes, there are other credible justifications available, but they are likely to be very controversial internationally. The Trump administration now appears to be arguing that the U.S. strike on Soleimani was in response to past and ongoing attacks on U.S. forces by Iran and Iran-supported proxy forces. The argument presumably then is that the U.S. actions were justified as self-defense against attacks that already occurred and were likely to continue to occur, or perhaps even escalate.

This argument has been criticized from many angles, each of which is complicated. A few are that the U.S. response was unnecessary or disproportionate, that the targeting of Soleimani personally was illegitimate, and that the United States violated Iraq’s sovereignty by targeting Soleimani on Iraqi territory.

Past U.S. administrations have also strained to justify their targeted killing programs. For instance, President Barack Obama was criticized by some for strikes against alleged terrorists in Libya, Somalia, and Yemen. What makes the Trump administration different?

The George W. Bush and Obama administrations did indeed justify U.S. targeted killing programs, taking the clear position that the United States was engaged in an ongoing war with al-Qaeda and affiliated terrorist groups. Additionally, Congress had approved U.S. strikes on al-Qaeda and associated forces through the 2001 Authorization for Use of Military Force.

Several features distinguish the Soleimani strike from past practices. Many critics see this month’s strike as dangerously escalatory and unlikely to disrupt Iranian threats. Moreover, the Trump administration has not explained its position on its shadow conflict with Iran—a state—or how targeting a top commander fit within applicable international law.

More generally, the Trump administration is making a mistake in not explaining clearly its legal justification for the Soleimani strike. Without a legal rationale, it is easy for critics to paint the killing as a political assassination, and the United States has an interest in promoting strong lines between that illegitimate practice and legitimate self-defense or wartime operations.

Even critics of the strike have acknowledged that Soleimani was a bad actor and an enemy of the United States and its allies. Do you think the public cares much about the legal rationale? Why should they? 

I don’t know whether the public cares, but they should care about the U.S. legal justification, even though Soleimani had a lot of American blood on his hands. The United States benefits from a system of rules that limits when and how states may use military force. It’s in the national interest to promote that system, and President Trump has made many damaging comments suggesting otherwise. Additionally, many U.S. allies care a lot about these legal questions, and strong cooperation depends on reaching some common, or at least consistent, answers to them.