The U.S. Can Deter Iran but Not Its Proxies

The assassination of Iranian military commander Qassem Suleimani met with widespread concern that U.S. foreign-policy decisions are devoid of any overarching strategic vision. As former U.S. Secretary of State John Kerry wrote in a critique of President Donald Trump’s handling of the Middle East, “Clearly he doesn’t do strategies, period.”

Yet the administration has articulated at least some strategy. In addition to justifying the assassination on the grounds of preventing an imminent attack, the president and his allies argue that it will deter what they describe as increasing Iranian aggressiveness. “[T]he Suleimani strike,” according to Sen. Tom Cotton, “has already restored deterrence.” In support of this deterrent strategy, Trump threatened, via his preferred medium of Twitter, massive further attacks should Iran choose to escalate the conflict. While his initial suggestion that the United States would target cultural sites has been walked back, the underlying threat of escalation in support of deterrence stands.

The problem with this bellicose posture is not that it is inherently unstrategic. The problem is that it is a strategy designed for a very different kind of conflict than the one the United States faces with Iran. To adapt former Defense Secretary Donald Rumsfeld’s phrase, you go to war against the adversary you have, not the adversary you want. Iran is not the Soviet Union. It has pursued a decades-long policy of cultivating alliances with armed proxy groups—and that means there’s a real risk this attempted deterrence will backfire, forcing an escalation sought by neither side.

In its most straightforward form, the logic of deterrence is simple: If an adversary believes the costs of an attack are high enough, it will prefer not to engage in that attack in the first place. Thus, the administration’s argument goes, if the United States threatens a massive response to Iranian aggression, they are likely to stand down.

But this logic rests on a couple of key assumptions. Most importantly, in this instance, those who are threatened with punishment must in fact have the power to prevent the precipitating attacks. For such threats to work, then, the Iranian regime itself must be in a position to decide whether or not attacks occur.

Iran has close ties to armed groups throughout the Middle East, from Yemen to Lebanon to Syria to Iraq. Many of these relationships were built in part by Suleimani himself. While these groups take weapons, training, support, and some degree of direction from Iran, they are also independent actors. Their preferences are not always aligned with Iran’s, and they have shown themselves willing to contradict Iranian directives when doing so is to their strategic advantage. For instance, Iran-aligned Houthi rebels have engaged in escalatory violence over the objections of their Iranian backers. This partial independence makes it difficult to attribute responsibility for attacks undertaken by such proxies.

Suppose one of the several armed Shiite groups with ties to Iran that are operative in Iraq engages in a significant attack in the coming days or weeks. It will be unclear whether that attack was taken at Iran’s direction or not. Will the United States extend its belligerent deterrent stand to such acts? Will it strike back at Iran for actions by Iraqis or Syrians?

The answer may well be yes. After all, it was not actions by the Iranian military but by Iranian proxies in Iraq that put in motion the chain of events leading to the killing of Suleimani. Kataib Hezbollah, an Iran-linked Shiite militia, was responsible for the rocket attacks on Iraqi bases in December 2019 that killed an American contractor and injured several soldiers. That event spurred a U.S. airstrike on Kataib Hezbollah’s headquarters in Iraq, which subsequently led to the protests outside the U.S. Embassy that preceded the killing of Suleimani.

In an important sense, then, the United States has already shown that it can be provoked by Iranian proxies. In so doing, America has put itself in a profoundly dangerous strategic position. In an attempt to deter Iran with maximalist threats, the United States has given independent armed militias the power to escalate conflict between two sovereign nations.

The Iranians appear acutely aware of the risk. Their initial response to the assassination was notably proportional and public. They wanted no misunderstanding. Moreover, the Iranian ambassador to the United Nations recently argued that Iran was responsible for these public actions but that it ought not be held responsible for “any sort of actions to be taken by others,” a clear reference to the risk of provocation by Iran-linked militias.

The problem is that, having publicly responded with face-saving missile strikes that did limited damage, Iran may genuinely prefer de-escalation. But its proxies, especially those operating in Iraq, may not. Perhaps they view greater conflict between Iran and the United States as an opportunity to end the ongoing U.S. presence in Iraq. Or perhaps they see strategic advantages to operating within the chaos of increased civil conflict.

In this case, they may well have incentives to engage in attacks—for instance, on Americans in Iraq—that exploit the United States’ more aggressive deterrent posture to manipulate it into greater conflict with Iran. And Iran may not be in a position to prevent those actions, in which case Trump’s deterrent stance will have backfired. Indeed, one might even worry that groups not linked to Iran, like the Islamic State, that wish to spread discord and chaos might view this as an opportune moment to engage in false-flag operations that make it look as though Iranian proxies are engaged in escalatory violence.

Of course, proponents of a maximalist strategy will argue that the alternative, backing off the deterrent threat, invites further bad behavior by Iran itself. And there is some truth to this. That is what is so frustrating about the contemporary conflict space, which is inevitably characterized by hard-to-attribute attacks associated with proxy groups, cyberwarfare, and terrorism. To a significant degree, deterrence, which has been a hallmark of U.S. strategy for generations, simply ceases to be an effective way to conceptualize keeping the peace.

But frustrating as this state of affairs is, it won’t do to simply pretend matters are otherwise. You fight the adversary you have. Salvation will not come simply in the articulation of a strategy. It requires a new vision, one better adapted to the contemporary challenge. Traditional deterrence provides too much opportunity for ill-intentioned and impossible-to-deter actors to manipulate the situation, creating escalatory spirals that neither the United States nor Iran truly desires.