Marines onboard the USS John P. Murtha observe an Iranian fast attack craft as it transits the Strait of Hormuz, off Oman. Donald Holbert/U.S. Navy/Handout via REUTERS
Briefing / Middle East & North Africa 20+ minutes

The Urgent Need for a U.S.-Iran Hotline

Naval incidents in the Gulf have spotlighted the danger that a U.S.-Iranian skirmish could blow up into war. The two sides have little ability to communicate at present. They should hasten to design a military-to-military channel to lower the chances of inadvertent conflagration.

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What’s new? Tensions between the U.S. and Iran have repeatedly brought the two sides to the brink of open conflict. While neither government seeks a full-fledged war, a string of dangerous tit-for-tat exchanges amid mounting hostile rhetoric underscores the potential for a bigger military clash.

Why does it matter? Due to limited communication channels between Tehran and Washington, an inadvertent or accidental interaction between the two sides could quickly escalate into a broader confrontation. The risk is especially high in the Gulf, where U.S. and Iranian military vessels operate close to one another.

What should be done? The U.S. and Iran should open a military de-escalation channel that fills the gap between ad hoc naval communications and high-level diplomacy at moments of acute crisis. A mechanism facilitated by a third party might contain the risk of conflict due to misread signals and miscalculation.

I. Overview

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.

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.

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.

II. Treacherous Waters

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.[fn]See Crisis Group Middle East Report N°205, Averting the Middle East’s 1914 Moment, 1 August 2019; and Crisis Group’s Iran-U.S. Trigger List.Hide Footnote 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.[fn]Crisis Group Middle East Report N°210, The Iran Nuclear Deal at Four: A Requiem?, 16 January 2020.Hide Footnote The COVID-19 pandemic could have opened a window for a ceasefire but instead appears to have become an occasion to display hardened positions.[fn]Crisis Group Middle East Briefing N°76, Flattening the Curve of U.S.-Iran Tensions, 2 April 2020.Hide Footnote 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.[fn]The Gulf was an arena for direct U.S.-Iran military confrontation during the waning months of the Iran-Iraq War. In 1987, the U.S. Navy launched Operation Earnest Will to protect U.S.-allied vessels in Gulf waters. In April 1988, as part of Operation Praying Mantis, U.S. forces sank or severely damaged half of Iran’s operational fleet days after a U.S. frigate struck an Iranian mine off the coast of Qatar. Tim Comerford, “Operation Praying Mantis demonstrates same priorities Navy values today”, U.S. Navy, 17 April 2013.Hide Footnote 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.[fn]Oriana Pawlyk, “CENTCOM: Iran never warned RQ-4 drone before shootdown”,, 30 July 2019; Michael D. Shear, Eric Schmitt, Michael Crowley and Maggie Haberman, “Strikes on Iran approved by Trump, then abruptly pulled back”, The New York Times, 20 June 2019; and “Iran says ‘illegal’ U.S. presence in Gulf causes insecurity”, Reuters, 17 April 2020.Hide Footnote 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.[fn]Remarks by President Trump at a Flag Presentation Ceremony”, White House, 18 July 2019.Hide Footnote Tehran denied the loss of any aircraft.[fn]Iranian Armed Forces reject Trump’s claim on downing drone”, Tasnim, 19 July 2019.Hide Footnote These incidents, occurring against the backdrop of Iran’s suspected involvement in several attacks from May to September 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”.[fn]Zachary Cohen, Kevin Liptak, Barbara Starr and Ryan Browne, “US Navy ship ‘destroyed’ an Iranian drone, Trump says”, CNN, 19 July 2019. On Operation Sentinel, see “U.S. Central Command Statement on Operation Sentinel”, U.S. Central Command, 19 July 2019; Mark Hoball, Arshad Mohammed and David Gregorio, “U.S. suspects Iran in tanker attack but cannot prove it now: official”, Reuters, 13 May 2019; “Secretary of State Michael R. Pompeo Remarks to the Press”, U.S. State Department, 13 June 2019; and “IRGC seizes smuggling fuel tanker near Abu Musa”, IRNA, 30 December 2019.Hide Footnote

The huge number of warships from many countries in the narrow Strait of Hormuz increases the odds of a mistake.

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.[fn]Crisis Group telephone interview, EMASoH official, 30 March 2020. EMASoH has no military-to-military communication channel, but it does have a diplomatic spokesperson. Crisis Group interview, French defence official, Paris, February 2020. Operation Sentinel and EMASoH have different mandates: whereas Sentinel seeks to deter hostile Iranian action through rapid response and pre-emption, EMASoH seeks to ensure a safe navigation environment by monitoring and de-escalating tensions. “European Maritime Awareness in the SoH (EMASOH): Political Statement by the Governments of Belgium, Denmark, France, Germany, Greece, Italy, the Netherlands and Portugal (20 January 2020)”, French Ministry for Europe and Foreign Affairs, 20 January 2020.Hide Footnote 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.[fn]Justine Barden, “The Strait of Hormuz is the world’s most important oil transit chokepoint”, U.S. Energy Information Administration, 20 June 2019.Hide Footnote 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”.[fn]Remarks at the Munich Security Conference, “Bridging Troubled Waters: De-escalation in the Gulf”, 15 February 2020.Hide Footnote

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”.[fn]Crisis Group telephone interview, former State Department official, 20 December 2019.Hide Footnote As part of its Operation Sentinel, the U.S. directs observation and rapid-reaction forces, including vessels and aircraft, to respond to incidents involving U.S., commercial or third-party state vessels.[fn]In the words of U.S. Secretary of Defense Mark Esper, “As long as you are in the area, that you can react quick enough to deter the provocation, that's the key”. Quoted in Todd Lopez, “Esper: Operation Sentinel Prevents Escalation of Middle East Waterways Conflict”, U.S. Defence Department, 24 July 2019. In addition to the U.S., there are seven other countries participating in the International Maritime Security Construct overseeing Sentinel: the UK, Saudi Arabia, the United Arab Emirates (UAE), Bahrain, Albania, Australia and Lithuania.Hide Footnote 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.[fn]Crisis Group interview, senior Iranian official, December 2019. “Spoofing” means impersonating another craft, often with the purpose of directing commercial traffic into Iranian or contested waters; “jamming” means interfering with a ship’s navigation signal and reception to impair its ability to navigate, often to direct it into Iranian or contested waters. Ryan Browne and Barbara Starr, “U.S. government warns of Iranian threats to commercial shipping, including GPS interference”, CNN, 7 August 2019.Hide Footnote

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.[fn]Crisis Group interviews, Washington, April 2020. See also “IRGCN vessels conduct unsafe, unprofessional interaction with U.S. naval forces in Arabian Gulf”, U.S. Central Command, 15 April 2020.Hide Footnote 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.[fn]U.S. Navy surface forces and Army helicopters conduct live fire exercise in north Arabian Gulf”, U.S. Central Command, 21 April 2020. CENTCOM has noted that such “integration operations” mirror those carried out during Operation Earnest Will in 1987. See “U.S. Navy surface forces and Army attacks helicopters conduct integration operations in Arabian Gulf”, U.S. Central Command, 1 April 2020.Hide Footnote 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”.[fn]Tweet by Donald J. Trump, @realDonaldTrump, U.S. president, 8:08am, 22 April 2020.Hide Footnote 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.[fn]IRGC calls U.S. claims fake, Hollywood scenario”, Mehr News, 19 April 2020.Hide Footnote

The existing communications infrastructure in the Gulf is insufficient to limit prospects of miscalculation or escalation. As the U.S. Air Force chief of staff, General David Goldfein, noted, “there is no deconfliction hotline nor any communications between the U.S. military and Iran, except for safety of operation radio calls on guard at the tactical level”. In other words, save for routine messages between ships in proximity, the U.S. and Iranian militaries do not talk to one another.[fn]Phil Steward and Michelle Nichols, “Why U.S.-Iran tensions could quickly escalate into a crisis”, Reuters, 24 May 2019.Hide Footnote These tactical, ad hoc communications between Iranian and U.S. vessels (“bridge-to-bridge communications”) leave officers of limited authority in charge of preventing unintended confrontations and containing them if and when they occur.

These deficiencies are compounded by the absence of institutionalised indirect lines of U.S.-Iran communication, apart from a Swiss diplomatic channel that links the two sides at senior levels. The latter channel allowed the U.S. to promptly convey red lines to Tehran after it killed the IRGC Qods Force commander, General Soleimani, for example, and permitted Iran to confirm receipt of and respond to U.S. messages, thus helping stop a dangerous situation from escalating further.[fn]Drew Hinshaw, Joe Parkinson and Benoit Faucon, “Swiss back channel helped defuse U.S.-Iran crisis”, Wall Street Journal, 10 January 2020.Hide Footnote Because the channel was designed for diplomatic, not military, communication, however, it may not prevent an incident during a standoff between military ships from turning into a shootout.

The Swiss diplomatic channel may not prevent an incident during a standoff between military ships from turning into a shootout.

In an incident during the Obama administration’s second term, in 2016, the IRGC detained ten U.S. sailors travelling aboard two riverine boats from Kuwait to Bahrain but that drifted into Iranian territorial waters. Then-Secretary of State John Kerry, who over the course of JCPOA negotiations had developed extensive direct contacts with his Iranian counterpart, was on the phone with Foreign Minister Javad Zarif within 30 minutes of learning of the incident, and the two spoke “at least five [times] … over a period of roughly ten hours”.[fn]U.S. Sailor Flap: Model for Diplomacy?”, U.S. Institute of Peace, 13 January 2016.Hide Footnote Iran released the boats and crew the following morning. Amid the current acrimony, when direct interaction between senior diplomats is scarce, Washington and Tehran would be unlikely to open a direct diplomatic channel in a moment of crisis. Furthermore, the U.S. blacklisted Zarif in 2019. While Twitter has provided an unusual means of direct communication and signalling between key officials on both sides, it is hard to see such a public platform being effective in preventing inadvertent escalation.[fn]For example, shortly after Iran’s 7 January missile strikes in Iraq, Foreign Minister Javad Zarif tweeted that “Iran took and concluded proportionate measures” in response to Soleimani’s killing, adding: “we do not seek escalation or war”. Tweet by Javad Zarif, @JZarif, Iranian foreign minister, 9:32pm, 7 January 2020. Minutes later, President Trump, also by tweet, declared that “all is well!” Tweet by Donald J. Trump, @realDonaldTrump, U.S. president, 9:45pm, 7 January 2020.Hide Footnote

Even before the present round of U.S.-Iran tensions which began in 2018, senior U.S. defence officials recognised the risks posed by the lack of an operational channel situated between tactical, bridge-to-bridge and strategic, diplomatic communications. They advocated establishing a channel that could help avert a misreading of signals between the U.S. and Iranian militaries.[fn]Crisis Group email correspondence, former U.S. Defense Department official, 25 March 2020.Hide Footnote Recognising this same dangerous potential for escalation, the U.S. Congress in December 2019 required that the executive branch submit a report on deconfliction channels with Iran.[fn]See Section 1227 of the 2020 National Defense Authorization Act (NDAA). It requires the president to submit a report on “the status of United States military-to-military deconfliction channels with Iran to prevent military … miscalculation” and “an analysis of the need and rationale for bilateral and multilateral deconfliction channels, including an assessment of recent United States experience with such channels of communication with Iran”. The report was to be submitted no later than 30 days after the NDAA became public law on 20 December 2019.Hide Footnote As of mid-April, the Trump administration had yet to do so.

III. Anatomy of a De-escalation Mechanism

While a U.S.-Iran de-escalation mechanism can draw on past U.S. experiences with military communications links with adversaries, including the Soviet Union, China, Russia and Iran-backed Iraqi paramilitary groups, it will require some innovation.[fn]There is precedent for U.S. military-to-military communication with adversaries, including U.S.-Soviet hotlines dating back to 1963, a U.S.-China defence telephone link set up in 2008, U.S. communications with Iraqi paramilitary groups during the counter-ISIS campaign (2014-2017) and an ongoing U.S.-Russia deconfliction channel in Syria.Hide Footnote In the absence of a U.S.-Iran Incidents at Sea agreement, such as the U.S. had with the Soviet Union, the two sides have limited means of keeping their respective naval forces separate through mechanisms such as “deconfliction lines” or “ops boxes” (temporary zones of exclusive operations).[fn]Incidents at Sea agreements, such as the 1972 U.S.-Soviet Incidents at Sea agreement, are typically binding bilateral agreements detailing standard procedures for avoiding incidents at sea (what some call “rules of the road”) and communicating after any mishaps that do occur.Hide Footnote Also unlike past cases, diplomatic communication lines supporting operational information exchanges between U.S. and Iranian personnel are few and far between, and the legality and feasibility of direct contact between the U.S. and Iranian militaries may be complicated by their reciprocal designations of the IRGC and CENTCOM as foreign terrorist organisations.[fn]Designation of the Islamic Revolutionary Guard Corps”, U.S. State Department, 8 April 2019; and Bozorgmehr Sharafedin, Peter Graff, Frances Kerry and Mark Heinrich, “Iran designates as terrorists all U.S. troops in Middle East”, Reuters, 30 April 2019.Hide Footnote

Efforts to establish a direct communication channel would also almost certainly encounter significant hurdles in Tehran and Washington. The Iranian military, the IRGC in particular, was reportedly instrumental in undermining the Obama administration’s 2011 attempt to set up a high-level military hotline between the two governments, both for fear of being perceived as legitimising a U.S. military presence in the region and due to Supreme Leader Ayatollah Ali Khamenei’s disdain for President Mahmoud Ahmadinejad, who reportedly favoured the idea.[fn]Tim Mak, “Iran hangs up on U.S. hotline”, Politico, 4 October 2011.Hide Footnote Too, the Trump administration’s coercive approach has dulled the appetite in Tehran for any sort of diplomatic engagement under duress. As an adviser to Ayatollah Khamenei put it:

The Trump administration has already reneged on the only agreement [the JCPOA] we had between the two countries in 40 years, has waged an all-out economic war against our nation, has assassinated our most popular general [Soleimani], and has not even agreed to loosen sanctions amid the COVID-19 crisis. Instead of thinking about a hotline, they should try to build some trust. Establishing a hotline would then be technically straightforward and easy to implement.[fn]Crisis Group interview, Tehran, April 2020.Hide Footnote

One should expect resistance in Washington as well. There, policymakers are sceptical both because they believe that Tehran would reject any U.S. proposal and because they are reluctant to engage Iran even on operational matters for fear of undercutting the pressure campaign with mixed messages. These factors may limit possibilities for even an indirect military communication channel.[fn]Crisis Group e-mail correspondence, former U.S. State Department official, 4 December 2019; and Crisis Group telephone interview, former U.S. State Department official, 20 December 2019. A former senior Iranian military official said he views the U.S. military as a “wise adversary … which has a more pragmatic view” toward a de-escalation channel than the more hawkish elements within the Trump administration, which may prevent consensus in Washington behind such an initiative. Crisis Group interview, former senior Iranian military official, Tehran, April 2020.Hide Footnote

A U.S.-Iran de-escalation channel would have to anticipate a number of potential problems.

Overcoming these obstacles will be challenging, especially given the wider diplomatic impasse and distrust between the two sides, but it is important to try. Since both leaderships seem keen to avoid uncontrolled escalation, the imperative of avoiding unintended conflict may conceivably take precedence over other duelling considerations. The most feasible structure for a U.S.-Iran de-escalation channel arguably would be for third-party intermediaries to link counterpart U.S. and Iranian officers of higher rank and authority, and on a more structured basis, than existing bridge-to-bridge communications.

Such a mechanism would have to anticipate a number of potential problems. For example, communication through an intermediary could become an unwieldy “telephone game”, especially if exchanges were to occur between officers of mismatched rank and authority.[fn]Crisis Group interview, former U.S. State Department official, Washington, 18 November 2019.Hide Footnote Factions within the U.S. and Iranian governments could also seek to undermine military-to-military communications within each side’s respective interagency process. Local commanders suspicious of the other side’s intentions might withhold vital information from their opposite numbers and officers might be hesitant to risk their careers by appearing amenable to cooperation with an arch-adversary.[fn]Crisis Group interview, former U.S. official with experience managing the U.S.-Russia deconfliction mechanism in Syria, Washington, 16 December 2019; and Crisis Group interview, former U.S. State Department official, Washington, 18 November 2019.Hide Footnote

That said, at least during the initial stages, an indirect, mediated de-escalation mechanism could make contacts more politically palatable for both parties.[fn]Crisis Group interview, former U.S. State Department official, Washington, 18 November 2019. The initial stage could last between three and six months, if not longer. Crisis Group telephone interview, U.S. official formerly assigned to U.S.-Russia deconfliction channel in Syria, 13 December 2019.Hide Footnote Being limited in scope and ambition, it would require no dramatic departure from the Trump administration’s “maximum pressure” approach. Nor would it entail Iran endorsing a U.S. military presence that it rejects as a matter of principle. But it would provide a safety valve that could prevent inadvertent escalation. Indeed, some former and current officials in Tehran and Washington suggest that, at a minimum, both governments would view the prospect of a mediated hotline with interest, given the present level of tension.[fn]Crisis Group interviews, Iranian officials, Tehran, November-December 2019; former senior U.S. Navy official, Washington, 24 March 2020.Hide Footnote

The first step toward establishing an indirect channel is to identify a viable third-party intermediary. The ideal candidate would combine deep expertise in Gulf navigation with experience in mediation and constructive diplomatic relations with both the U.S. and Iran. Based on these considerations, Oman would be a particularly strong candidate.[fn]Crisis Group telephone interviews, former U.S. Navy official, 24 March 2020; former CENTCOM official, 26 March 2020; former U.S. Defence Department official, 25 March 2020; senior Omani officials, Muscat, January 2020; and senior Iranian officials, Tehran, March 2020.Hide Footnote It manages security for ships exiting the Strait of Hormuz into the Gulf of Oman, and as a result has technical acumen and expertise in relaying communications. It has previously facilitated U.S.-Iran communication. And both sides have typically considered it an honest broker.[fn]Crisis Group interviews, senior Omani officials, Muscat, January 2020; and Crisis Group telephone interview, former U.S. Navy official, 26 March 2020.Hide Footnote Oman has a military cooperation agreement with the U.S., and jointly operates a military commission with Iran.[fn]Among the Gulf countries, Oman has also had the closest historical relations with Iran, providing it with a unique platform of trust on which to further develop regional cooperation initiatives.Hide Footnote It has held separate joint exercises with the Iranian and U.S. militaries, most recently in April and September 2019, respectively.[fn]For the Oman-U.S. military cooperation agreement, see “U.S. Relations With Oman”, U.S. Department of State, 27 November 2019. For joint military exercises, see “Military forces of Iran, Oman hold joint naval rescue, relief drills”, Press TV, 18 April 2019; and Ramadan Al Sherbini, “Oman conducts military drill with US, Britain”, Gulf News, 9 September 2019.Hide Footnote Omani officials have expressed interest in facilitating military-to-military communications as an intermediary between the U.S. and Iran as long as both sides ask for it.[fn]Crisis Group interviews, Omani officials, Muscat, and email correspondence, January-March 2020. The January 2020 leadership transition does not appear to have affected Oman’s foreign policy or support for such an initiative.Hide Footnote

Omani officials have expressed interest in facilitating military-to-military communications.

European or other extra-regional third parties may not be as effective as Oman due to a lack of trust between Iran and U.S.-allied European powers with forces deployed to the region. Within the region, intra-Gulf Cooperation Council sensitivities may discourage other GCC members from offering themselves as a third party.[fn]Crisis Group interviews, U.S. Defense Department officials, Washington, April 2020.Hide Footnote Alternatively, the UN could appoint an observer based in the region to act as an intermediary or establish a mechanism for monitoring Iran-U.S. communication and mediating in case of an unintended clash. The UN has extensive experience across a broad range of conflicts facilitating links or providing intermediaries between adversaries. Yet Iran appears to have greater appetite for dealing with a national government than with an international organisation.[fn]Crisis Group interviews, Iranian political and military officials, Tehran, November-December 2019.Hide Footnote The UN may also have insufficient access in Tehran to get in touch quickly with the military’s upper echelons.[fn]Crisis Group interview, UN official, New York, 16 January 2020.Hide Footnote

The second element relates to the rank, authority and specialisation of the persons on each side responsible for managing the communication channel. In the best-case scenario, they would be high-ranking officers with direct access to both the most senior in-theater commanders and decision-makers in their respective capitals, and the ability to manage communications without a large support staff. They should occupy the rank of colonel or higher, whether in a U.S. combatant or component command or in Iran or Oman’s General Staff.[fn]Crisis Group telephone interviews, former senior U.S. Defense Department officials, 13 December 2019 and 24 February 2020.Hide Footnote It might be wise to build multiple layers of contacts between officers of ascending rank and authority, so that during escalating crises intermediaries can quickly work up the chain of command.[fn]Crisis Group telephone interview, former CENTCOM official, 26 March 2020.Hide Footnote In one possible design, a one-star general in CENTCOM’s leadership would communicate by telephone with an Omani general maintaining a separate telephone line with a counterpart on the Iranian General Staff.[fn]This design could involve a U.S.-Oman telephone line, an Oman-Iran telephone line and an “air gap” between the two that physically separates the system’s components to prevent infection by malware and other attempts at espionage. Crisis Group telephone interview, former senior U.S. Navy official, 24 March 2020.Hide Footnote

Critics of such a mechanism may contend that, owing to rancour between Tehran and Washington, establishing even a line of contact for operational de-escalation is likely to encounter insurmountable political opposition. They may also say it will prove ineffectual even if established.[fn]Crisis Group telephone interview, former senior U.S. State Department official, 20 December 2019; and Crisis Group interviews, former senior Iranian military officials, Tehran, April 2020.Hide Footnote Although the critics could be right, high-ranking current and former Iranian and U.S. officials have told Crisis Group that they believe this mechanism is both needed and viable, and that the mechanism’s potential to prevent a catastrophic miscalculation and inadvertent escalation outweighs its costs and risks, even if its remit is limited.[fn]Crisis Group telephone interviews, former U.S. Defense Department officials, December 2019-February 2020; and Crisis Group interview, senior Iranian official, Munich, February 2020.Hide Footnote

At a time when neither side is likely to deem direct links appropriate yet both want a means of de-escalating at dangerous moments, use of an intermediary such as Oman could help reduce tensions and build confidence in the mechanism without limiting either party’s room for manoeuvre. Indeed, if it works, the mechanism could be developed into a direct channel – without requiring changes to broader policy – and replicated in other theatres.[fn]Crisis Group interview, former U.S. State Department official, Washington, 18 November 2019; Crisis Group telephone interview, official formerly assigned to U.S.-Russia deconfliction channel in Syria, 13 December 2019; and Crisis Group telephone interview, former U.S. Navy official, 24 March 2020.Hide Footnote In a future less beset by mutual antagonism, such a communication channel might even help undergird a U.S.-Iran Incidents at Sea agreement.

Use of an intermediary such as Oman could help reduce tensions and build confidence in the mechanism without limiting either party’s room for manoeuvre.

IV. Conclusion

Establishing a U.S.-Iran de-escalation mechanism would be an insurance policy against accidental eruption of conflict. Like the Swiss channel, which in January 2020 underscored the value of having clear lines of contact in anticipation of or in response to incidents with escalatory potential, and ongoing bridge-to-bridge communications, this additional mechanism would serve both sides’ interest in managing their standoff. It would also serve a useful force protection role without requiring political concessions or a shift in strategic posture. Even amid tit-for-tat military exchanges, the mechanism would allow the two sides to take action to avoid missteps that would broaden the conflict into a war neither appears to want. Intermediaries, such as Oman, can play an important role in setting up a communications mechanism of this sort, initially focused on the Gulf region. Over time, if it proves its worth, it could be upgraded to become a direct channel and be replicated in other flashpoints.

The U.S. and Iran are likely to have an acrimonious relationship as long as the underlying tension between “maximum pressure” and “maximum resistance” lingers – and perhaps well beyond that point. But in the absence of a major diplomatic breakthrough, an indirect military communications channel could go some way toward ensuring, at least, that a single incident will not spark a wider conflagration.

Washington/Tehran/Brussels, 23 April 2020

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