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The events of the so-called Tanker War in the Persian Gulf remain benchmarks in Iranian and U.S. military thinking and offer issues for U.S. senior leaders to reconsider should they again be faced with having to deter Iran in a fast-breaking crisis. Recently declassified material affords additional insights into the challenges of engaging Tehran during Operation Earnest Will, the U.S. Navy effort to escort and protect reflagged Kuwaiti tankers against potential Iranian attack, particularly during the war’s last years in 1987 and 1988. Earnest Will presented challenges in understanding Iranian decisionmaking, producing persuasive intelligence, messaging Iran, achieving deterrence without unintentional escalation, and discovering diplomatic offramps. Although decades have since elapsed, U.S. leadership might have reason to recall the following lessons from that operation should the United States face a bounded, but prolonged, conflict with the Islamic Republic:

• Iran’s decisionmaking was opaque to U.S. policymakers and military planners. The gaps in understanding core issues such as regime strategic intent, the firmness of Tehran’s resolve to undermine the tanker escort regime, and the reliability of its command and control complicated the military planning process.
• As the Intelligence Community (IC) sought to offer “truth to power” supported by carefully reasoned, prescient national intelligence estimates, a disconnect developed between the IC and senior military leadership over how Iran might respond to Earnest Will.
• Messaging Iran was a fraught process complicated by failures to establish reliable, direct, and timely crisis communications with Tehran; difficulties in crafting a persuasive message to a regime hardened by 7 years of war with Iraq; and the guesswork in proving that any messaging effort worked.
• Achieving deterrence while not unintentionally expanding a conflict with Tehran was a central challenge to U.S. policy that was revealed in the National Security Council (NSC)’s conservative approach to reviewing options for rules of engagement (ROEs) and responding to Tehran’s repeated provocations.
• The United States, its allies, and Iran recognized diplomatic offramps that might end the maritime conflict, but no actor succeeded in persuading Baghdad to permanently stop its attacks on shipping to Iran, Tehran’s central requirement for halting the Tanker War.

We revisit this 34-year-old history to learn from hundreds of U.S. and British documents declassified since 2010 that address diplomacy, NSC and United Kingdom (UK) cabinet deliberations, current intelligence reporting, and military threat assessments during Earnest Will. The reporting augments a body of archival evidence released in the United States in the first two decades after the Iran-Iraq War (1980–1988), additional secondary sources, and earlier memoirs and oral histories by U.S. leaders who helped craft strategy during the period.1

To put this more recent evidence into perspective, however, we first offer a thumbnail sketch of the operation. The bulk of this article then highlights the dynamics and complexities of each of the five challenges cited above. Finally, we close with a few thoughts about Earnest Will, recalling choices that might haunt U.S. decisionmakers in 2022.

The Operation

Earnest Will was the U.S. response to Kuwait’s request for maritime protection in the seventh and last year of the Iran-Iraq War. Iraq expanded the war to the Gulf in 1984 by attacking Iranian shipping in attempts to force Iran to accept a ceasefire and hinder its ability to export oil, its primary source of foreign exchange. Iran, unwilling to accept a ceasefire, reciprocated, but it generally responded to Iraqi ship attacks on a tit-for-tat basis while preferring to confine the war to land, where it enjoyed significant advantages.2

Kuwait in December 1986 asked Moscow to protect its tankers, and the U.S. Government seriously began considering a similar request by the spring of 1987. Iran perceived Kuwait as a near-cobelligerent to Iraq, however, given the economic aid it was providing and Kuwait’s willingness to allow its ports to serve as primary points for arms transshipments to Iraq.3 Tehran saw U.S. assistance to Kuwait as a step toward widening the war, tilting the military balance toward Iraq and sharply increasing foreign naval presence in the Gulf—all developments it was determined to avoid.

Nevertheless, despite some domestic opposition, the Ronald Reagan administration was willing to protect 11 reflagged Kuwaiti tankers starting in July 1987 for a variety of reasons, including a general tilt in favor of Iraq in its war with Iran, a preference to block the Soviet navy from the region, a principled commitment to freedom of navigation, and a desire to buttress allies in the Gulf Cooperation Council (particularly after recent revelations of U.S. military assistance to Tehran as part of the Iran-Contra affair).4

The U.S. operation would also be controversial in Tehran. Iranian military and diplomatic responses to the operation probably were driven by perceptions of asymmetries of national will and relative readiness of the two nations to sustain casualties should an incident between them escalate. Based on Tehran’s history of combative posturing in the face of threats, its hostile rhetoric, and an attack on a Soviet vessel in May 1987, the IC judged that Iran would attempt to bring an early end to superpower protection of Kuwait ships.5 This mindset contributed to a series of attempts to hinder the operation and test U.S. resolve from the operation’s start in July 1987 until the summer of 1988 when Iran finally accepted a ceasefire.

Iran Opaque

Correctly assessing an adversary’s decisionmaking calculus is central to grand strategy and military planning. Unfortunately, Iran’s decisionmaking was opaque to the IC, with the result that consumers could receive mixed answers to questions on issues such as Iran’s depth of commitment to the war, control of operational commanders, and willingness to escalate quickly using more capable systems such as Silkworm antiship cruise missiles (ASCMs).6 A contemporary Central Intelligence Agency (CIA) memorandum characterized the problem as one of incomplete evidence by stating, “No one has all the information and, based on the limited facts, disagreement existed on the degree of threat.”7 In a similar vein, Rear Admiral Harold Bernsen, then commander of Middle East Force, later lamented in his oral history that it was “very difficult to ferret out specific details concerning leadership decisionmaking. I never saw any report, and certainly no report to be authoritative. So what you really did was make your assumptions based on what you knew about them, their track record.”8

Fissures Between the IC and Consumers

A primary responsibility of the IC is to offer truth to power using carefully reasoned, transparent assessments even if they contain unpopular conclusions, particularly when the documents address such difficult topics as regime strategic intent and potential crisis behavior. The success of such efforts is never guaranteed, in view of previous cases in which the IC did not persuade decisionmakers to accept its conclusions. In this case, attempting to gauge Tehran’s response to the escort regime, the IC informed but did not persuade all senior leaders about its judgments concerning Tehran’s probable responses to Earnest Will. A lengthy special National Intelligence Estimate (NIE) published in June 1987 and supporting assessments collectively warned that Iran over the next year had the will to challenge Earnest Will with escalatory steps starting with terrorism and conventional attacks against unescorted Kuwaiti ships, including the reflagged tankers. If unable to dissuade the United States from using such tactics, however, Iran would eventually attack an escorted reflagged tanker. Tehran might even attack a U.S. warship directly given the perceived threat that successful completion of the operation would pose to long-term Iranian interest in attaining hegemony over the Gulf.9

The estimate was timely because its publication coincided with heated congressional hearings over whether the United States should undertake the operation. President Reagan and Secretary of State George Shultz subsequently alluded to the NIE, which was controversial among policymakers and in Congress.10 CIA Director William Webster’s prepared remarks later stated, “Our view is not one that the policy community welcomed.”11 Admiral William Crowe, then Chairman of the Joint Chiefs of Staff, subsequently challenged the assessment’s validity:

The critical question in this case was not a matter of capabilities, but of what Iran’s willingness would be to engage in a sea war. On this issue there was little history to follow, and the IC experts were speculating. They did not know, though they certainly had opinions. When the appraisals came in, they offered highly alarming “worst case” scenarios. The prospects of success were nil; the whole Gulf would be aflame. That, in general terms, was the intelligence estimate, and our opponents in Congress loved it.12

Some senior military commanders seemed unwilling to conclude that Iran would directly challenge the convoy. Historian David Crist judged that their mindset betrayed an underlying assumption that Tehran would be deterred by the mere presence of U.S. naval power and would not resort to a direct attack on Earnest Will units even after it had mined the approaches to Kuwait:

No one in Tampa or Washington bothered to change the assumption guiding the American convoy operations. Admiral Bernsen [Commander, Middle East Force], General George Crist [Commander, U.S. Central Command (USCENTCOM)] and Admiral Crowe continued to believe that Iran would never dare take such an overt action against the U.S. Faith in the deterrent effect of the carrier and American firepower clouded every level of American thinking.13

The military also chafed over the extent of influence the IC should have in evaluating the military planning effort. Admiral Crowe added to the discussion, “The experts in the IC did not believe they had been formally and adequately consulted. It seemed to me that up to this point our problem was more political than military, and I did not think intelligence types should control the decision. But this was a matter I should have handled more carefully.”14

Despite such criticism and challenges, Webster rightfully defended the NIE in 1988 as a model of truth to power and a demonstration of IC resistance to politicization. He noted in a public speech that the problem had arisen when “policymakers had gotten ahead of the IC in making certain decisions, including the reflagging of tankers without knowing what all of the implications of their actions were.”15 Webster publicly summarized the episode in 1988 when he stated, “There was some grousing that perhaps they [policymakers] ought to be allowed to have something to say about how the assessment worked. . . . We made it very clear that our estimates would be the best we could produce. They would not for any political reason, or policy reason, be changed.”16

Messaging Tehran Problematic

Messaging an adversary is central to deterrence and crisis management. Tehran in 1987, however, rebuffed repeated U.S. attempts to establish more reliable, direct communications. Tehran offered no interlocutor for either U.S. senior leadership authorities or tactical commanders in theater to approach and demonstrated no interest in any kind of hotline or deconfliction circuit. Repeated U.S. warnings against behavior such as mining were ineffectual, although other U.S. admonitions may have resonated in Tehran.17

Secretary Shultz publicly announced in September 1987 that he wanted direct communication with Tehran so that “it is clear exactly what is being communicated, and so the more direct it is probably the better.”18 He particularly wanted to warn and dissuade Iran, stating, “They should have it clear in their mind the strength of our determination and not make any miscalculation about that”—a potential nod to IC warnings about the risks of Iranian overconfidence.19

The State Department again raised the issue in November 1987, this time approaching the United Kingdom. A U.S. memorandum noted that Washington had frequently used indirect communications to explain U.S. policy to Tehran, what the U.S. Navy and U.S. flag vessels were and were not doing in the Gulf, and to specify the circumstances that could require U.S. forces in international waters to exercise their right of self-defense. The note welcomed an opportunity to communicate directly through authorized Iranian government officials to clarify the U.S. position and reduce the risk of Iranian miscalculation.20

Although unable to establish direct communications with a senior Iranian official, Washington sent Tehran démarches and other indirect communications. Washington sought to assure Tehran of U.S. neutrality in the Iran-Iraq conflict, explain the rationale for Earnest Will, dissuade Tehran from again boarding U.S. flag vessels, and deter Iran from attacking U.S. ships, particularly by launching its new Silkworm ASCMs or by laying mines. Washington also sent messages to Tehran to help limit a conflict, particularly after the United States attacked Iranian oil platforms and warships in April 1988.21 The démarches themselves, however, acknowledged that Iran was not heeding U.S. warnings. Tehran would instead launch Silkworms at merchant ships near Kuwait and lay mines along Earnest Will convoy transit routes.22

Boardings. After Iran boarded the U.S. flag merchant ship President Taylor and interrupted its radio communications on January 12, 1986, Washington asserted its rights as a neutral power. Immediately after the incident, the United States démarched Tehran, concluding that the visit and search of U.S. flag vessels during a period of heightened tension and regional conflict “could lead to a confrontation between U.S. and Iranian military units.”23 American diplomats viewed the document as laying down a red line for the Iranians, according to reporting from the UK embassy in Washington.24 The United States subsequently warned Iran at the beginning of Earnest Will in July 1987 that no belligerent search party would be permitted aboard U.S. flag vessels.25

Silkworm ASCMs. Washington was particularly concerned about Tehran’s deployment of Silkworm ASCMS early in 1987 because the missile qualitatively changed the maritime threat and could seriously damage or sink combatants and tankers with its 1,100-pound warhead.26 Consequently, the United States sent warnings to dissuade Tehran from using the missile while crafting plans to destroy it.27 Perhaps reflecting IC perception that Islamic Revolutionary Guard Corps command and control might be unreliable, the United States warned Iran, “We consider the activities of the Islamic Revolutionary Guard Corps in the Persian Gulf or elsewhere to be the responsibility of the Islamic Republic.”28

Mines. Although U.S. decisionmakers initially were more concerned about the Silkworms, they also repeatedly warned Iran against laying mines to hinder U.S. ships.29 Shultz advised his British counterpart in April 1988:

Four times last fall, we informed the Government of Iran that we could not accept Iran’s mine laying in international waters or in the waters of neutral states. We made clear we did not seek further confrontation with Iran, but indicated we would be prepared to meet any escalation of military actions by Iran with strong countermeasures.30

Seeking Deterrence While Avoiding Unintentional Escalation

U.S. policymakers repeatedly had to balance their twin goals of maintaining deterrence while avoiding a wider war during Earnest Will. Reconciling these objectives would be particularly problematic given the IC’s warnings about the danger of escalation and Tehran’s determination to frequently test U.S. resolve. Admiral Crowe did not share the IC’s perceptions, but he did move additional forces into the region to preserve escalation dominance. He subsequently wrote, “I did not believe the Iranians were going to challenge us seriously, but I wanted to make sure that if they did we could hit them with overwhelming power.”31

The military tendency to offer harsher crisis responses than policymakers would want to implement was apparent during Earnest Will as well. Although U.S. military commanders prepared more robust retaliatory plans to respond to increasingly serious incidents, the military found little appetite to approve them in Washington, according to the participants. U.S. retaliatory measures conducted through April 1988 were insufficient to shatter Tehran’s resolve to continue attacking merchant ships. Only unfavorable developments culminating that summer—including loss of domestic support for the war and sweeping Iraqi victories—would convince Supreme Leader Ayatollah Khomeini to accept a ceasefire and only then because the state’s very survival was at stake.

As Earnest Will loomed, the United States reviewed its ROEs and began contingency planning, particularly for responding to a potential Silkworm attack against an Earnest Will convoy while maintaining tight national control.32 Washington subsequently prepared plans for military responses after the reflagged tanker Bridgeton struck an Iranian mine in July 1987, a Silkworm ASCM damaged the reflagged tanker Sea Isle City in Kuwait in October 1987, and an Iranian mine nearly sank the USS Samuel B. Roberts in April 1988. Declassified national records and older sources such as memoirs and oral histories show that U.S. policymakers envisioned proportional damage to Iranian military targets with limited loss of life, sought to bound the incidents and to avoid escalation, and were leery of striking the Iranian mainland despite planning by subordinate military commanders for more extensive strikes.

Despite the emphasis on tactical readiness to defend against attack after Iraq’s inadvertent Exocet missile attack on the USS Stark in May 1987, however, Washington continued to constrain potential U.S. naval responses to an Iranian attack. In the National Security Planning Group (NSPG) meeting on May 18, 1987, participants commented that any response was to be limited to the actual attacker, and Iran’s land mass could not be attacked without approval from Washington.33 The UK embassy in Washington reported that its contacts on the Chief of Naval Operations staff had confirmed on June 8, 1987, that the ROEs for Middle East Force and the carrier battle group also excluded preemptive strikes. The embassy also wrote that its State Department and NSC contacts had confirmed that although preemption against the Silkworms had been one of the full range of options the United States considered, those sources “uniformly” stated preemption had few adherents.34

Estimates from the IC also may have pushed national policymakers toward moderation in contingency planning. The National Intelligence Officer for Near East and South Asia in June 1987 highlighted the implications of an extensive attack on Iran: “They will not be easily intimidated. Even the threat of a major U.S. strike on Iranian shore facilities may not be sufficient [to make Iran back down] given the massive destruction already experienced and the vital Iranian interests at stake.”35 That August, the IC assessed that a major U.S. attack on Iran could be counterproductive: a U.S. attack that caused heavy Iranian casualties and damage would not guarantee a change in Iranian policies but would afford militant elements an opportunity to spur the population to greater sacrifice.36

Such concerns notwithstanding, developing responses to potential Silkworm attacks occupied military planners for much of the spring and summer of 1987.37 The NSC required DOD and the Joint Staff to provide an update on Tomahawk Land Attack Missile–C planning for possible strikes against the Silkworm sites (as well as tactical air support requirements for Middle East Force surface combatants) in May 1987.38 The NSC revisited the issue in June 1987, when Ambassador Robert Oakley, assistant to the President for Middle East and South Asia, wrote that the NSC needed to work with the Defense Department and State Department on contingency planning and response scenarios for the range of potential Iranian threats, “from terrorist attacks on U.S. facilities to mining to suicide small boat attacks to use of Silkworms.”39

The Joint Staff prudently planned for a range of courses of action, although the more extreme ones probably were unpalatable to the administration. The bulk of the initial planning probably was complete before August 1987, when National Security Adviser Frank Carlucci told British Prime Minister Margaret Thatcher that the United States had prepared options “ranging from action against mine storage facilities to a major strike against Bandar Abbas. Any retaliation would be proportionate. But no decisions had been taken.”40 President Reagan in fact seemed interested in avoiding escalation. When Thatcher warned him in July 1987 that it was important not to escalate the conflict, he agreed, stating that the United States would only act in self-defense in response to an attack.41

Bridgeton Mining

The United States considered military strikes against Iran after the reflagged tanker Bridgeton struck an Iranian mine near Farsi Island on July 24, 1987, but the level of damage and the ambiguity of the attack did not cross the NSC’s threshold for warranting reprisals. Discussions with Reagan in the NSPG meeting on that date suggested a cautious approach with the tone being a “calm and steady course,” in Reagan’s words, with focus on the need first to find out what really had happened to Bridgeton.42 Secretary of Defense Caspar Weinberger subsequently wrote, “We considered retaliation but showed restraint, particularly since damage was limited and no personal injury occurred.”43

The UK embassy in Washington 3 days later described a “muted” U.S. reaction to the mining. Noting that it had approached its contacts in the NSC, Pentagon, and State Department, the embassy detected no pressure for military retaliation. The lack of casualties and conclusion that the incident was “not a clear-cut attack by Iran helped keep the temperature down,” according to the embassy.44

Admiral Crowe, a participant in several debates about potential U.S. retaliatory contingency operations against Iran, perceived restraint in national policymaker discussions of potential responses for Bridgeton as well as subsequent discussions about retaliation for attacks against the reflagged tanker Sea Isle City and USS Samuel B. Roberts. Crowe commented that State Department participants in the meetings insisted each time that retaliation be proportionate.45 He elaborated, “Retaliation, they believed, had to be seen as a simple, clear response, not in any sense an escalation, and in this way they were usually seconded by the National Security Advisor.”46

Operation Nimble Archer

U.S. leaders again considered retaliating against Tehran after a Silkworm struck Sea Isle City in Kuwait on October 16, 1987. The declassified record corroborates statements by some participants that most U.S. policymakers envisioned a limited response against an offshore Iranian military target that would risk relatively few casualties. Ultimately, a U.S. Navy surface action group attacked two platforms in the Rashadat (formerly Rostam) oilfield with naval gunfire on October 19, 1987, in Operation Nimble Archer.

In discussing the deliberations over retaliation, Reagan and Weinberger approved of selecting the Rashadat platforms because they were limited targets with military value and risked few casualties on either side. Reagan mentioned that the NSPG discussed selection of targets that would entail “minimum risk to personnel—theirs and ours.”47 Weinberger stated that the principals selected it after a debate because it was a staging area for small boat and helicopter attacks and served as a listening post collecting against U.S. ship movements.48

Supporting the planning, General George Crist, the USCENTCOM commander, subsequently submitted a statement for the International Court of Justice stating that he had wished to strike a military target while avoiding escalation: “I believed the best way of undermining Iran’s ability to attack U.S. forces was to degrade their ability to observe our forces—in effect, put out their eyes.”49 He, too, hoped to avoid further escalation of war with Iran and maintain U.S. status as a nonbelligerent. He noted, “The Rostam platforms were unambiguously offshore—not Iranian land territory.”50 Attacking them would have the added advantage of minimizing the danger of civilian casualties, especially since, he noted, the United States had warned of the impending attack and allowed people to evacuate before the firing commenced.51 But General Crist did not allude to more robust courses of action that secondary sources state were being concurrently prepared by lower military echelons.52

Rear Admiral Harold Bernsen, then the Navy commander in the Gulf, also sensed the national-level debate was bounded to avoid escalation. In a subsequent oral history, he stated, “A great many things were debated. . . . Those rather radical solutions were—except for in some quarters—dismissed pretty much out of hand. No one in Washington in retrospect really was interested in an all-out attack on Iran.”53

The British wrote in November 1987 that discussions with State Department officials involved in planning the operation confirmed that U.S. national-level policymakers were attempting to maintain a posture combining “restraint, determination, and resolve.”54 They noted, however, there was still support for the argument that “only action or the threat of action affecting Iran’s ability to prosecute the war against Iraq was likely to deter Iran.”55 The memorandum elaborated:

• The decision reflected Reagan’s cautious attitude to the general issue of retaliation, use of U.S. military power, and the risk of casualties. He personally added a 20-minute evacuation warning for the Iranians on the oil platform. Furthermore, the response against the oil platforms (the lowest-profile military option that was put to him) included a list of six possible targets, only one of which the President chose.56
• The United States drew a clear line between options involving any action against Iranian territory (mainland and offshore islands) and other actions against Iranian military assets offshore (aircraft, ships, platforms). The British account noted that there was and would still be the greatest U.S. reluctance to attack mainland targets.57
• U.S. ROEs called for an immediate response by local commanders to any Iranian attack on a U.S. flag merchant vessel or warship. The British were told that “a satisfactorily full immediate reaction would limit the demand for a secondary later response in retaliation or self-defense.”58

Operation Praying Mantis

The administration’s debates about how to retaliate for the mining of USS Samuel B. Roberts in the southern Persian Gulf on April 14, 1988, were wider ranging than those over Nimble Archer or Bridgeton, judging from an account offered by David Crist.59 The dynamics between those proposing more robust military solutions and officials pushing to bound the conflict were more apparent. Crist reported that although there was a consensus to retaliate for the mining, members of the administration were divided on how to respond. In a separate account, Reagan himself noted restraint as he wrote in his diary, “We didn’t want to kill—but to destroy those properties,”60 a sentiment the military would have been well aware of given its participation in NSPG meetings. In a meeting held to discuss options on April 16, 1988, Defense Secretary Carlucci similarly wanted no loss of life on either side and a very restrained retaliation—“little more than a couple of platforms,” according to Crist’s monograph.61 Crist elaborated:

Neither Secretary of Defense Carlucci nor National Security Adviser [Colin] Powell had much enthusiasm for a large attack against Iran, and both advocated moderation. “No one has been killed,” Powell cautioned in a meeting in the Situation Room. “We don’t want to expand this conflict.” He brought up the possibility of grave environmental damage to the Gulf should one of the platforms be destroyed and tens of thousands of gallons of oil spilled. Carlucci seemed to agree with his old NSC deputy and expressed an almost obsessive concern with avoiding casualties, both American and Iranian. He insisted that any U.S. attack needed to be preceded by a warning.62

Both the Chairman of the Joint Chiefs of Staff and the USCENTCOM commander sensed national reluctance for a large retaliatory strike. Admiral Crowe summarized the national-level deliberations in his memoirs: “They were dealing in perceptions; what they really wanted to do was make something out of nothing. That meant striking a blow that would not hurt the Iranians so much that they would be moved to escalate, but that would at the same time impress the American public as the act of a strong and determined leadership.”63 General Crist stated, “No one, however, supported an attack on the Iranian mainland. The only condition in which they would attack Iran proper would be if the Iranians launched their Silkworms against U.S. ships, at which time all bets were off.”64

General Crist, Admiral Crowe, and Vice Admiral Anthony Less, the commander of Joint Task Force Middle East, however, had pushed for greater retaliation after the Roberts minestrike.65 Admiral Crowe explained to the Joint Staff that General Crist wanted heavy retaliation. Admiral Less had proposed destroying the naval headquarters in Bandar Abbas and mining the port, thereby bottling up the Iranian navy.66 Admiral Crowe was concerned that the retaliation would be understated, saying that this time Iran had gone too far and a mere tit-for-tat response was not enough: “We have to let Tehran know that we are willing to exact a serious price, forcefully arguing to sink a ship.”67

In addition to sinking an Iranian combatant, President Reagan agreed to sink the Iranian naval auxiliary Charak, the ship suspected of laying the mines that struck Roberts.68 However, locating the unit was problematic. Washington assessed that Charak, last seen in port on April 12, was the minelayer and Washington was searching for the Charak on April 15, according to UK embassy reporting.69 President Reagan wrote in his diary that on April 21, 1988 (3 days after Praying Mantis), he gave permission to board the vessel and, if mines were found aboard, to remove the crew and sink it. The next day, however, Reagan was informed the ship had returned to port.70

Diplomatic Offramp Tested

The United States also sought to use diplomacy to end—or at least to suspend—the Tanker War with brief success in August 1987. London and Washington agreed that the maritime conflict might be paused if Baghdad could be persuaded to stop maritime attacks against Iranian interests.71 They judged that Iran’s approach to the Tanker War operations was generally retaliatory; Tehran’s ship attacks tended to follow Iraqi maritime airstrikes. Both the United Kingdom and the United States judged that Tehran might halt its ship attacks if Iraq did so.72

London and Washington accordingly agreed to pressure Baghdad directly or via its Gulf Cooperation Council allies to halt ship attacks in the hope that Tehran would do likewise.73 In fact, the UK cabinet concluded on July 23, 1987, that the most important requirement in the immediate future was to end the ship attacks: “The government was doing everything possible to mobilize pressure for this on Iraq and Iran. There was hope that the message might have some effect.”74

Iraq indeed reluctantly agreed to halt the attacks—a major concession given the role they played in Baghdad’s strategy to keep international focus on the Gulf and to motivate Tehran to end the ground war. Ship attacks in the Persian Gulf stopped for much of August 1987. Unfortunately, Baghdad resumed airstrikes against tankers and oil installations on August 29, and Tehran resumed ship attacks 2 days later.75

Iran raised the issue the following month but failed to secure another lengthy hiatus in Iraqi ship attacks, probably because of Baghdad’s dissatisfaction with the lack of any progress on the diplomatic front. In its démarche to Washington, Tehran outlined its perception that the United States was not acting as a neutral party but implied that Iran would again consider stopping its ship attacks. The Iranians wrote, “Exerting pressure on the regime of Iraq to continue to refrain from attacking the marine targets in the Persian Gulf and the exit of foreign forces can be a very good guarantee for safeguarding the security in this region, the free export of oil, and the freedom of international cooperation.”76

Conclusion

The challenges and lessons discussed herein remain relevant in evaluating a future military crisis with Iran, although admittedly Iran has grown more powerful and less war-fatigued since Khomeini reluctantly accepted the ceasefire, effectively ending the long, bloody Iran-Iraq War in mid-1988. A few following thoughts address these challenges in 2022.

Iran’s decisionmaking process probably remains opaque, although its decisionmaking calculus can be modeled. The most vexing part of preparing an assessment of wartime behavior of any potential adversary such as Iran can be the assessments of probable behavior before and during a conflict. Much of the information in such an assessment is simply not knowable because the adversary has not decided what to do. In other words, analysts are forced to investigate an intelligence mystery, a contingent development that cannot be known with certainty. The results can be unsatisfying to consumers should the resultant judgments constrain friendly military operations or portray an adversary as having boundless resolve no matter what courses of action Washington takes.

Establishing crisis communications as was proposed during Earnest Will can still be problematic if a potential adversary such as Iran has a penchant for relying on deniability and an incentive to complicate U.S. decisionmaking by withholding information. Additionally, for messages to be effective, they also must be persuasive when a country such as Iran weighs them against the salience of their original strategic objectives or the U.S. track record in responding to previous provocations.

The phenomenon of daylight between the IC and consumers is not unusual; it has recurred since 1988 and is likely to be seen again when the IC’s message clashes with policymaker or military objectives. Efforts to make the estimative process more transparent while using absolutely rigorous analytic tradecraft probably have helped preclude some of the rancor experienced in 1987–1988, but the tensions are unlikely to go away completely.

Balancing the risks of deterrence against avoiding unintended escalation remains a central challenge to planning. It is the challenge of our senior military leadership to ensure plans are congruent with the national leadership’s strategic intent while simultaneously offering them a sufficient range of choices.

Although the United States sought consistently to help facilitate an end to the Iran-Iraq War—particularly its naval component—it lacked the diplomatic leverage to pressure Iraq to permanently suspend its ship attacks. Still, the search for offramps is embedded in crisis management and will remain critical in helping to bound conflicts. JFQ

Notes

1 For some of the best secondary sources on Operation Earnest Will, see David Crist, The Twilight War: The Secret History of America’s Thirty-Year Conflict with Iran (New York: Penguin Press, 2012); Harold Lee Wise, Inside the Danger Zone: The U.S. Military in the Persian Gulf, 1987–1988 (Annapolis, MD: Naval Institute Press, 2013); Lee Allen Zatarain, America’s First Clash with Iran: The Tanker War, 1987–88 (Philadelphia: Casemate, 2010); Then–Chairman of the Joint Chiefs of Staff Admiral William C. Crowe and Secretary of Defense Caspar Weinberger devoted lengthy sections in their memoirs to the operation. See William Crowe, The Line of Fire: From Washington to the Gulf, the Politics and Battles of the New Military (New York: Simon & Schuster, 1993), 186–211; Caspar Weinberger, Fighting for Peace: Seven Critical Years in the Pentagon (New York: Warner Books, 1990), 387–428.

2 Central Intelligence Agency (CIA), “The Tanker War: Ship Attacks in the Persian Gulf,” June 1987, available at <https://www.cia.gov/readingroom/docs/DOC_0000268293.pdf>.

3 CIA Special Analysis, “Iran: Growing Threat to Persian Gulf Shipping,” May 30, 1987, available at <https://www.cia.gov/readingroom/docs/DOC_0000252949.pdf>.

4 Weinberger, Fighting for Peace, 387–428.

5 CIA, Special National Intelligence Estimate (NIE), “Iran and the Superpowers in the Gulf,” June 1, 1987, available at <https://www.cia.gov/readingroom/docs/CIA-RDP89B00224R000903140005-5.pdf>.

6 See Richard A. Mobley, “Intelligence and Operation Earnest Will, 1987–1988,” Studies in Intelligence 60, no. 3 (September 2016), for background on the Intelligence Community’s role in Earnest Will.

7 CIA internal memorandum for Director, Office of Congressional Affairs, Request for Persian Gulf Hearing on Differences in Assessment between the Agency and the Department of Defense, June 17, 1987, CREST CIA-RDP90B0017R000300710004-0.

8 Paul Stillwell, Reminiscences of Rear Admiral Harold J. Bernsen (Annapolis, MD: Naval Institute Press, 2014), 24.

9 CIA, “Iran and the Superpowers in the Gulf,” 3–6.

10 George P. Shultz, Turmoil and Triumph: My Years as Secretary of State (New York: Scribner, 1993), 529; Ronald Reagan, The Reagan Diaries (New York: HarperCollins, 2007), 509.

11 CIA, proposed remarks by William H. Webster, Director of Central Intelligence, before American Business Conference, Washington, DC, March 23, 1988, available at <https://www.cia.gov/readingroom/docs/CIA-RDP99-00777R000302120001-6.pdf>.

12 Crowe, The Line of Fire, 182.

13 Crist, The Twilight War, 240.

14 Crowe, The Line of Fire, 182.

15 CIA, remarks by William H. Webster, Director of Central Intelligence, to Phoenix Rotary Club, January 15, 1988, available at <https://www.cia.gov/readingroom/docs/CIA-RDP99-00777R000301900002-0.pdf>.

16 Ibid.

17 Secretary of State message, “USG Proposal for Direct Official Channel with Iran,” September 16, 1987, Digital National Security Archive (DNSA); U.S. diplomatic note, “U.S. Readiness to Meet with a Senior Iranian Official,” November 8, 1987 (delivered by U.S. Embassy London to Foreign & Commonwealth Office [FCO] on November 12, 1987) (FCO 8/7251), The National Archives (United Kingdom) (TNA).

18 “USG Proposal for Direct Official Channel with Iran.”

19 Ibid.

20 “U.S. Readiness to Meet with a Senior Iranian Official.”

21 Message from United Kingdom (UK) embassy, Washington, DC, “US/Gulf,” (FCO 8/7251), TNA; memo from private secretary, “The Gulf,” April 19, 1988 (FCO 8/7251), TNA.

22 FCO Research Department, “Iran Annual Review,” 1987–1988 (FCO 8/7050), TNA.

23 Enclosure to letter from UK embassy, Washington, DC, March 10, 1986, démarche to Iran on President Taylor incident, January 1986 (FCO 8/6329), TNA; White House, “Statement by Principal Deputy Press Secretary Speakes on Iran’s Search of the United States Merchant Ship President Taylor,” January 13, 1986, available at <https://www.reaganlibrary.gov/archives/speech/statement-principal-deputy-press-secretary-speakes-irans-search-united-states>.

24 Letter from UK embassy, Washington, DC, “Shipping in the Gulf: U.S./Iran,” March 10, 1986 (FCO 8/6329), TNA.

25 U.S. submission to International Court of Justice (ICJ) (Exhibit 42), “Démarche to Iran: Use of Silkworms/Protection Regime,” July 18, 1987.

26 CIA memo, “Iran’s Silkworm Antiship Missile Capability,” July 2, 1987, available at <https://www.cia.gov/readingroom/docs/CIA-RDP90T00114R000700410001-6.pdf>.

27 Weinberger, Fighting for Peace, 397; Démarche to Iran, “Message to Iran,” May 23, 1987 (attachment to National Security Council memorandum, “Messages to Iran,” June 8, 1987), William J. Burns Files, Ronald Reagan Presidential Library (RRPL); U.S. submission to ICJ, “Démarche to Iran: Use of Silkworms/Protection Regime.”

28 U.S. submission to ICJ, “Démarche to Iran: Use of Silkworms/Protection Regime.”

29 Untitled message from Secretary of State Shultz to UK foreign minister, April 18, 1988 (FCO 8/7251), TNA; U.S. submission to ICJ (Exhibit 56), “Message for the Government of Iran,” August 31, 1987.

30 Untitled message from Shultz to UK foreign minister.

31 Crowe, The Line of Fire, 189.

32 Minutes from National Security Planning Group (NSPG) meeting, “U.S. Policy and Gulf Security,” May 18, 1987, DNSA; untitled letter from Secretary of State to President of the Senate, May 20, 1987, NSC NESA Directorate Staff Files, RRPL.

33 NSPG minutes, “U.S. Policy and Gulf Security,” May 18, 1987, DNSA.

34 Message from UK embassy, Washington, DC, “U.S./Gulf: Silkworm,” June 8, 1987 (FCO 8/6816), TNA.

35 CIA memorandum from National Intelligence Officer for Near East/South Asia, “Warning and Forecast Report for Near East and South Asia,” June 3, 1987, available at <https://www.cia.gov/readingroom/docs/CIA-RDP91B00776R000300060012-0.pdf>.

36 CIA NIE, “The Persian Gulf: Implications of a U.S.-Iranian Confrontation,” August 1987, available at <https://www.cia.gov/readingroom/docs/DOC_0005557215.pdf>.

37 UK Ministry of Defence memorandum, “Note of a Meeting between the Rt Hon. J. Stanley and General Robert Herres, Vice Chairman, JCS,” April 2, 1987 (DEFE 13/2389), TNA; NSC memo, “Follow-up on May 22 PRG on U.S. Policy and Gulf Security,” May 22, 1987, available at <https://www.cia.gov/readingroom/docs/CIA-RDP89B00224R000400940001-9.pdf>; NSC memorandum, “NSPG on Persian Gulf Policy,” June 16, 1987 (Executive Secretariat files), RRPL; Memorandum from private secretary, “Prime Minister’s Meeting with Mr. Carlucci: The Gulf,” August 3, 1987 (DEFE 13/2390), TNA.

38 NSC memorandum, “Follow-up on May 22 PRG on U.S. Policy and Persian Gulf Security.”

39 NSC memorandum from Robert B. Oakley, “NSPG on Persian Gulf Policy, June 16,” June 16, 1987, Executive Secretariat Files, RRPL.

40 Memorandum, “Prime Minister’s Meeting with Mr. Carlucci: The Gulf.”

41 Memorandum from private secretary to PM, “Prime Minister’s Visit to Washington: Meeting with President Reagan,” July 18, 1987 (FCO 8/6755), TNA.

42 NSC minutes, NSPG Meeting, July 24, 1987, Executive Secretariat, NSC, NSPG Records, RRPL.

43 Weinberger, Fighting for Peace, 404.

44 UK embassy, Washington, DC, “U.S./Gulf.”

45 Crowe, The Line of Fire, 200–201.

46 Ibid.

47 Reagan, The Reagan Diaries, 538.

48 Weinberger, Fighting for Peace, 419–420.

49 U.S. submission to ICJ (Exhibit 48), letter from General George B. Crist re Nimble Archer planning, May 17, 1997.

50 Ibid.

51 Ibid.

52 Crist, The Twilight War, 255–257, 287.

53 Stillwell, Reminiscences of Rear Admiral Harold J. Bernsen, 124.

54 Memorandum from UK embassy, Washington, DC, “U.S./Iran: Contingency Planning,” November 25, 1987 (FCO 8/7251), TNA.

55 Ibid.

56 Ibid.

57 Ibid.

58 Ibid.

59 Crist, The Twilight War, 320–338.

60 Reagan, The Reagan Diaries, 597.

61 Crist, The Twilight War, 336.

62 Ibid.

63 Crowe, The Line of Fire, 201.

64 Crist, The Twilight War, 336.

65 Ibid., 334–338; Crowe, The Line of Fire, 200–203.

66 Crist, The Twilight War, 355.

67 Ibid., 336.

68 Ibid., 326–327, 334–337.

69 Message from UK embassy, Washington, DC, “Mining of U.S. Warship in the Gulf,” April 15, 1988, TNA.

70 Reagan, The Reagan Diaries, 599.

71 See Richard A. Mobley, “London and Washington Maintaining Naval Cooperation Despite Strategic Differences During Operation Earnest Will,” Naval War College Review 74, no. 2 (Spring 2021), for background on Anglo-American naval cooperation during the operation.

72 Private secretary (prime minister), “Prime Minister’s Visit to Washington: Meeting with President Reagan,” July 18, 1987 (FCO 8/6755), TNA; FCO to select embassies worldwide, message, “Iran/Iraq,” November 15, 1987 (FCO 8/6766), TNA.

73 Cabinet meeting conclusions, July 23, 1987 (CAB 128/87/1), TNA; Private secretary, “Prime Minister’s Visit to Washington Meeting with President Reagan;” FCO, untitled memorandum re meeting between Secretary of State Shultz and foreign minister, July 20, 1987 (FCO 8/6755), TNA; Prime minister to emir of Kuwait, untitled letter, July 24, 1987 (FCO 8/6559), TNA.

74 Cabinet meeting conclusions, July 23, 1987 (CAB 128/87/1), TNA.

75 FCO Research Department, “Iran Annual Review, 1987.”

76 Iranian démarche to United States, September 10, 1987 (attachment to NSC memo from Executive Secretary, “Recent Exchanges with the Government of Iran”), n.d., DNSA.