The U.S. and Iran have come perilously close to full-fledged military conflict thrice in the past eleven months. The tensions emanate from the Trump administration’s “maximum pressure” campaign against Iran and Tehran’s “maximum resistance” response, both triggered by the U.S. decision to withdraw from the nuclear deal and reimpose economic sanctions. Neither side appears to be seeking a war, but both have heightened the risk of one by engaging in provocative acts with little ability to communicate. As illustrated by President Donald Trump’s 22 April threat to “shoot down” any Iranian boat harassing U.S. ships, the danger may be greatest in the Gulf and Strait of Hormuz, where oil tankers and naval vessels help clog the sea lanes. The adversaries’ incapacity to communicate instantly when incidents happen opens the door to unintentional escalation if one side misreads the situation and, as a result, miscalculates. Establishing an operational channel, facilitated by a third party such as Oman, could minimise risks of such a scenario. If successful, a mechanism of this type could be replicated in other regional flashpoints.
This briefing outlines the need for a U.S.-Iran de-escalation channel and identifies its key elements. It is based on nearly three dozen interviews with current and former U.S., European, Omani and Iranian officials with experience operating in the Gulf and familiarity with past efforts at military-to-military communication between the U.S. and its adversaries, including, most recently, the U.S.-Russia deconfliction line in Syria and channels to the Popular Mobilization Units (PMUs) during the counter-ISIS campaign in Iraq.
U.S.-Iranian frictions have been growing since the Trump administration’s May 2018 decision to leave the Joint Comprehensive Plan of Action (JCPOA) and reimpose sanctions. The risks rose again a year later, when the U.S. revoked sanctions exemptions allowing Iran’s remaining customers to import its oil and Tehran began responding with nuclear and regional escalation. (1) The dynamics of “maximum pressure” and “maximum resistance” have brought the two sides to the brink of war three times: first in June 2019, after Iran shot down a U.S. drone; then that September, when Iran stood accused of attacking Saudi Arabia’s oil infrastructure; and again in January 2020, when the U.S. killed General Qassem Soleimani, triggering retaliatory Iranian missile strikes in Iraq. (2) The COVID-19 pandemic could have opened a window for a ceasefire but instead appears to have become an occasion to display hardened positions. (3) With neither side willing to yield, no effective communication channel and an arc of flashpoints where the U.S., Iran and their respective allies are juxtaposed, a single incident could spin out of control.
The Gulf, in particular, is an arena where even a minor skirmish could easily spark an unintended conflict. (4) Such a scenario nearly played out on 20 June 2019, when Iranian forces shot down a U.S. Global Hawk drone that Tehran claimed, contra Washington’s denials, had entered Iranian airspace. The incident came close to prompting retaliatory U.S. airstrikes on the Iranian mainland. (5) Less than a month later, on 18 July, the USS Boxer, an amphibious assault ship, downed an Iranian drone in the Strait of Hormuz. President Trump described this action as “defensive”, saying the drone had come within 1,000 yards of the U.S. vessel, reportedly failing to respond to repeated warnings.(6) Tehran denied the loss of any aircraft. (7) These incidents, occurring against the backdrop of Iran’s suspected involvement in several attacks from May to Sep tember 2019 on international shipping and Gulf energy infrastructure, prompted the U.S. Central Command (CENTCOM) to announce on 19 July that it would launch Operation Sentinel to “increase surveillance of and security in key waterways … in light of recent events”. (8)
Since late February 2020, other stakeholders in Gulf security, including European states, have also deployed vessels to the Gulf to monitor and de-escalate tensions. One such deployment is the European-led Maritime Awareness in the Strait of Hormuz (EMASoH) mission. (9) As a result, one of the narrowest chokepoints in the world, through which roughly one third of the world’s seaborne oil passes daily, is crowded with both civilian and military vessels. (10) The dense traffic increases the risk of accidents. Oman’s foreign minister, Yusuf bin Alawi bin Abdullah, warned in February: “The huge number of warships from many countries in the narrow Strait of Hormuz increases the odds of a mistake. Our message to all our friends … is to be cautious”. (11)
These risks are even higher regarding interactions between Iranian and U.S. military vessels amid growing tensions between the two countries. A former U.S. official said: “When we and the Iranians operate in the Gulf, it’s like two people in a phone booth”. (12) As part of its Operation Sentinel, the U.S. directs observation and rapidreaction forces, including vessels and aircraft, to respond to incidents involving U.S., commercial or third-party state vessels. (13) From its side, Iran, which rejects any U.S. claim to having a legitimate military presence in the Gulf, has spoofed bridge-to-bridge communications and jammed vessels’ GPS signals. (14)
U.S. officials also assert that Iranian fast attack craft persistently provoke both commercial and military vessels in the area, including most recently on 15 April 2020 when eleven Islamic Revolutionary Guard Corps (IRGC) navy speedboats harassed a formation of six U.S. warships in the Gulf, at one point coming within ten yards of a collision despite radio warnings and horn blasts. (15) The U.S. forces were undertaking “joint integration operations” between ships and attack helicopters as part of a series of exercises, some including live fire, that began in March. (16) Following the incident, Trump announced that he had “instructed the U.S. Navy to shoot down and destroy any and all Iranian gunboats if they harass our ships at sea”. (17) The IRGC rejected the U.S. version of what transpired on 15 April, contending that it was the U.S. vessels that had carried out “unprofessional and provocative actions”. Too, the IRGC maintained that it had “in recent weeks … witnessed the recurrence of unprofessional behaviour” by U.S. forces and “increased the capacity of its naval patrols” in response. (18)