Deterring by detection: A cheap, successful way to deter Iran

A vital part of Iran’s long-running grey zone warfare strategy is plausible deniability, as they most often work through proxies in the Middle East. And so the easiest way to keep Iran from taking action, write Bilal Y. Saab of the Middle East Institute and Frank McKenzie, who served as US Central Command chief from 2019 to 2022, is to make sure the Islamic Republic knows the spotlight is on them. 

Of all the security challenges the United States has faced in the Middle East, perhaps none has been bigger than deterring Iranian aggression. This mission has been the cornerstone of US Central Command (CENTCOM) for decades, and yet it is the one with which it has struggled the most.

During the Trump administration, US deterrence was, as one of us described it, “contested.” This meant that the United States was and still is able to deter Iran from committing the most egregious acts —  including producing a nuclear weapon and launching strategic attacks against collective security interests — but less able to prevent it from waging lower-level violence against US bases and regional partners.

CENTCOM has learned over the years that Iran’s style of asymmetric warfare — below the threshold of conventional war, but still able to hold people and property at risk — is really hard to deter or contain because the Iranians are good at it, given their extensive network of loyal Shi’ite militias across the region. This allows them to obfuscate their ultimate responsibility for many of these attacks, which is key to their strategy.

However, US deterrence against Iran’s gray-zone tactics is not a lost cause. In fact, the simple act of letting Iran know the US is paying attention may end up being the cheapest, most effective way of deterring their actions — with the benefit of being the kind of deterrence partners and allies in the region can amplify.  By denying the Iranians what they’ve coveted the most and excelled at for years — plausible deniability — the United States was able to establish a different form of deterrence — what could be termed “deterrence by detection.”

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This concept is not new — in fact, it has wide application in the civilian world with would-be criminals and even misbehaving children. The idea is that if someone who is about to cause mischief knows that they are being watched and their wrongdoing can be made public, they just might think twice before committing their offense to avoid humiliation and/or attribution.

In the spring of 2019, US intelligence showed that Iran was posturing for attacks against US troops and bases in Iraq, in response to both the US policy of maximum pressure and a perception that the United States was withdrawing forces from the region. CENTCOM responded by flying manned aircraft and sophisticated intelligence, surveillance, and reconnaissance (ISR) assets, including the RQ-4 Global Hawk and MQ-9 Reaper, above the heads of Iranian military personnel to let them know that it was watching their every move. The loud, buzzing sound of the US aerial equipment made it impossible for the Iranians to miss it. In other words, they knew that CENTCOM was closely monitoring their activities. This approach is assumed to have aided US deterrence. It’s impossible to prove it, of course, because many other factors could have been at play, but a reasonable case can be made that robust ISR did help.

The second episode in which a similar dynamic might have happened is much more recent. In early November of this year, the United States and Saudi Arabia deliberately went public with intelligence indicating Iran may attack the kingdom or Erbil, Iraq. This was an attempt by Washington, and to some extent Riyadh, to signal to the Iranians that any violence against American or friendly targets in the region would be directly attributed to Tehran. In the end, no attack was launched. Once again, it’s hard to demonstrate that deterrence worked but it’s not outlandish to believe that it did, given the quality of the intelligence at the time.

Neither of these two examples guarantees that deterrence by detection will always work with Iran, or any other adversary, particularly one geared up for more classical warfare. In February, Marine Commandant Gen. David Berger used the phrase “deterrence by detection” when describing the US’s attempts to convince Russia not to invade Ukraine by releasing regular public information about Moscow’s actions. Ultimately, every contingency is unique. Deterrence success also requires that the adversary believes that you are willing to punish them if they attack or are perceived to be preparing for an imminent attack. So, political will is at the heart of all forms of deterrence.

It hasn’t always been clear if and when the United States is willing to use force to respond to Iranian aggression. But that’s not all entirely bad because this lack of clarity arguably keeps the Iranians guessing. For example, the successful — and surprising — US strike on Iranian Quds Force commander Qasem Soleimani in January 2020 has made it harder for the Iranians to calculate when and where the United States might respond to their violence.

If one thinks of deterrence in terms of multiple layers — as one should — the ISR layer is extremely important. Simply put, if you can’t see your adversary preparing for an attack, you most likely won’t be able to deter them. The idea here is that not only do you constantly monitor their activities, but you make sure to show them that you are. The use of these capabilities has the great value of ensuring a range of any future contingency options for the United States and its partners. In addition, these capabilities produce information and build knowledge, which is always helpful, particularly in a coalition network.

The intent behind deterrence by detection is certainly not to replace other forms of deterrence, be it deterrence by denial or deterrence by punishment. Rather, it is to serve as a companion to them. It’s obvious that CENTCOM’s approach, which typically relies on sending bombers, fighter jets, and aircraft carriers as a show of force to the Iranians has failed. It’s time to think of something different and more cost-effective.

Now, given that advanced ISR capabilities are expensive and in high-demand especially in the Indo-Pacific region, there’s a limit to how much CENTCOM can use them in the theater. This is where regional partnerships are paramount. Washington should incentivize regional partners to invest in more persistent and effective ISR capabilities and ultimately integrate them with US capabilities. Where a local government might not have the money to invest in a bomber to fly near Iran’s borders, the majority of regional partners can afford to buy a fleet of ISR assets that can make it clear to Iranian forces that they are being watched, recorded and tracked.

That’s precisely what’s happening at sea, with the US Fifth Fleet’s latest initiative to create a vast, integrated network of manned and unmanned sensors — from seabed, to surface, to space — to more effectively patrol the waters of the region. Now, the United States must replicate this innovative, joint, and combined approach in the air and space domain to achieve more comprehensive deterrence against Iran.

Deterrence by detection is neither a sure thing nor without its technical challenges. But at the very least, and especially if combined with other forms of deterrence, it should raise the costs for the adversary should they be determined to pursue harmful courses of action against US and collective security interests.

Bilal Y. Saab is Senior Fellow and Director of the Defense and Security Program at the Middle East Institute. Frank McKenzie, a former CENTCOM commander, is a Distinguished Senior Fellow at the Middle East Institute