Michael Eisenstadt, the Kahn Fellow and director of Military and Security Studies at the Washington Institute for Near East Policy (WINEP), spoke to a May 10 Middle East Forum webinar (video) about U.S. deterrence against Iran's "gray zone" mode of warfare, the subject of his January 2020 WINEP manuscript.
The Iranian regime's modus operandi differs from the U.S. approach to war and peace. "When Americans talk about war, they think about go big or go home," said Eisenstadt. "Iran's way of war is completely different," and is a "deeply rooted aspect of the regime's strategic culture." Iran's "meat grinder" experience during the 1980-1988 Iran-Iraq war led the regime to develop strategies for inflicting costs on its adversaries while avoiding escalation into all-out war.
Iran's "gray zone modus operandi is designed to defeat the adversary's deterrence efforts" by "testing and probing to determine adversary response thresholds" and tailoring activities to stop short of triggering costly vertical escalation. The idea "is so simple that my kid brother understood it when we were growing up," explained Eisenstadt:
So I'd be sitting here at my desk doing my homework, and he would come to my room, stand right by the doorway, and start making noise, trying to annoy me, and trying to get my attention. I tried to ignore him doing my homework. And then he would start throwing little rolled up pieces of paper ... skip[ping] across my desk, and I'd try to ignore it. And he'd step one step into my room and one step back. Two steps in, two steps back. And then three steps. But finally that was it. He crossed my response threshold. I'd get up and start running after him. ... He'd had his door slightly open. So he had his anti-access area denial already ready. He would slide into his room, close the door, and lock it so I couldn't catch him.
The main difference between this kind of kid's play and the real world activities of gray zone actors is that kid brothers want to provoke a response in order to experience the thrill of the chase. Real world gray zone actors want to see what they can get away with without provoking an armed response.
Iran's campaign to discourage the Trump administration's "maximum pressure" sanctions policy reflects the same kind of strategy. It began in May 2019 with "limpet mine attacks against ships that were at anchor" in the Persian Gulf. When that didn't elicit a forceful U.S. response, Iran escalated to "limpet mine attacks against ships that were moving." In the following months it progressed to "attacks on Saudi oil facilities ... using cruise missiles and drones from multiple launch points."
When the U.S. didn't respond to Iran's devastating September 29 attack on a Saudi Aramco facility – which crossed a "long standing U.S. red line" regarding "the free flow of oil at reasonable prices from the Gulf" – Iran's proxies upped the ante in Iraq, progressing from "non-lethal activities, in terms of harassment and rocket fire" on American targets to "lethal activities when they finally killed an American in December with rocket fire."
The death of an American precipitated an escalation that led to the U.S. targeted killing of Gen. Qassem Soleimani, the head of the Quds Force of Iran's Revolutionary Guards, which "had a devastating psychological effect" on the Iranians. The U.S. response to Iran's proxy attacks had hitherto been limited to targeting the proxies, not Iran. Following Soleimani's demise, Iran's proxies continued with rocket and missile attacks on U.S. bases in Iraq, but generally were careful to avoid killing Americans.
"A great power that has worldwide commitments" (like a teenager with homework to do) can't "respond to every ... provocation," said Eisenstadt. The question, then, is how to respond in a way that best discourages further provocations. Excessive restraint will "embolden the adversary and [it] will try to push the boundaries." Excessive pressure risks cornering the adversary and goading it into lashing back, while potentially escalatory actions risk sparking a domestic and foreign backlash.
Tactical unpredictability in U.S. responses "makes it more difficult [for the Iranians] to assess risk."
A second key principle here is that you want an adversary to be uncertain about what it can get away with. Although it's important to consistently communicate and enforce America's "red lines" regarding freedom of navigation in the Persian Gulf, the free flow of oil from the region, and the killing of Americans, "there are times when it's good to be unpredictable." Being "more unpredictable" in how the U.S. responds "makes it more difficult [for the Iranians] to assess risk" and encourages them to be "more conservative and risk averse in their decision-making."
After "an increase in Iranian activity during the summer" of 2020, Eisenstadt noted, the Iranians "stopped almost everything" during the runup to the U.S. presidential elections in November, presumably because they thought "perhaps President Trump would be motivated to hit Iran hard ... [to] give him a bump at the polls." There was no way to reliably assess his response threshold, so the Iranians played it safe.
Since the election and Joe Biden's inauguration in January 2021, the Iranians have been trying to assess the new administration's response threshold, with increased non-lethal rocket attacks against American assets in Iraq and a "renewal of harassment in the Gulf." If the Biden administration's commitment to diplomacy with Iran constrains its responses to provocations, Iran will take full advantage of that.
The conventional "go big or go home" approach to Iran has produced "at best a mixed result."
The conventional approach to the conflict with Iran, which has produced "at best a mixed result" in past decades, won't suffice to deter Iran from engaging in activities that damage U.S. interests, said Eisenstadt. The U.S. needs to develop its own "gray zone strategy for dealing with Iran," through sustained activities that don't cross Tehran's fundamental red lines (unless vital American interests are at stake), including deniable covert operations and encouraging actions by allies. The "best way to fight fires is with fire in this case."