US Military Requirements for Assured Deterrence
While there can never be certain deterrence, Cold War presidents often had confidence that the United States had sufficient military power to support a policy of containment through a strategy of deterrence; for most of the period they felt that deterrence was assured. It is worth repeating Dean Acheson’s basic formulation: “American power would be employed in stopping [Soviet aggression and expansion], and if necessary, would inflict on the Soviet Union injury which the Moscow regime would not wish to suffer.”128 Assured deterrence began with assured destruction of the Soviet regime.
Having briefly assessed Iran’s behavior by the standard measures of deterrence theory, it seems plain that a similar assured-destruction, assured-regime-change capability is required to have confidence in a policy of containment and a strategy of deterrence toward Tehran. Indeed, Iran’s actions are at least as likely, if not more likely, to be erratic and provocative than were Soviet actions. Thus it would seem that a policy of Iran containment based upon a strategy of deterrence must meet the basic Cold War standard of credibility, which included three criteria. The first was an adequate US nuclear arsenal of offensive systems, what became the triad of bombers capable of carrying nuclear weapons, land-based ballistic missiles, and then submarine-launched ballistic and cruise missiles. While US nuclear doctrines shifted, encompassing highly detailed scenarios for nuclear exchange to simple mutual-assured destruction, the fundamental strategic requirement was widely accepted and long-standing. The second element was a substantial investment in forward-deployed and reinforcing conventional forces. In Germany, for example, the permanent covering force numbered in the hundreds of thousands (and usually included theater nuclear forces) backed up by the potential for rapid and large-scale reinforcement, translating into a “10 divisions in 10 days” measure. Again, specific war-fighting doctrines changed with technologies and circumstances, but there was broad consistency of approach through the decades. Third, the deterrent posture depended on the preservation of strong alliances that permitted relatively good policy integration, military cooperation, and basing and access for US forces. The United States swore to defend Europeans and Asians, but Europeans and Asians agreed to provide the battlefield as well as their own forces. All in all, the success of this inherently complicated endeavor demanded an immense and sustained US effort.
The nucleus of the Cold War deterrent system was the US nuclear arsenal, which by the end of the conflict numbered more than 20,000 warheads and thousands of delivery systems. Properly defining a US nuclear deterrent for Iran would require greater analysis than the scope of this paper can offer, but a number of broad requirements are apparent. To begin with, nuclear deterrence must be persistent: dedicated forces must be active, available, and present, at least in the mind of the adversary. These qualities were regarded as essential for Cold War deterrence and an underlying strategic logic. They were also reflected in the nuclear force-planning and operational concepts of the era, in the readiness rates and alert status of aircraft and ICBMs, and in deployment rates for nuclear submarines.
Further, the United States offered an extended nuclear deterrent to its allies around the world not only to prevent the use of Soviet short-range systems but also to lessen the opportunities to exert political pressure by such threats. In addition to forces based in the United States, a variety of theater nuclear forces were deemed critical. The divisive debate over the deployment of Pershing II intermediate-range missiles in Germany—agreed as necessary by both the German and US governments—reflected the underlying strategic reality. Secretary of State Clinton struck a strikingly similar strategic note in 2009. Though she carefully refrained from mentioning nuclear forces directly, the logic of her argument was familiar:
We want Iran to calculate what I think is a fair assessment that if the United States extends a defense umbrella over the region, if we do even more to support military capacity of those in the [Persian Gulf], it’s unlikely that Iran will be any stronger or safer, because they won’t be able to intimidate and dominate as they apparently believe they can once they have a nuclear weapon.129
The role of US offensive nuclear forces as an extended deterrent or the central feature of a defense umbrella covering US friends and allies and their interests across the greater Middle East will be critical. Such an extended deterrent is not only essential for assuring those like Saudi Arabia and Turkey, which at present do not possess nuclear forces of their own but have the means and, in the face of a nuclear Iran, the motive. It is also important for reassuring those who already possess nuclear systems—the Israelis, in particular. The region is already highly unstable, and a nuclear Iran would make it more so. Absent a credible US offensive deterrent—one that is present, persistent, and appropriate—the prospects for a policy of containment are bleak.
Current US nuclear force-planning and operational concepts remain keyed to Russian forces and the ongoing arms-control negotiations with Russia.130 It is beyond the scope of this report to specify precisely what a sufficient deterrent force would be in regards to Iran, but the prior point is that some Iran-specific element of US nuclear forces is required to give effect to the strategy of deterrence. To put it bluntly, Tehran must be certain that the United States has appropriate, proximate, and present nuclear forces, that punishment or denial is certain. In the Cold War, such strategic demands resulted in the deployment of theater nuclear forces (including intermediate-range ballistic missiles) and nuclear weapons designed to allow for counter-force strikes, that is, limited nuclear strikes against Soviet nuclear forces rather than only counter-value, or massively destructive, options.
In sum, adopting a policy of containment and a policy of deterrence would have implications for US nuclear policy and forces. However, current policies and plans do not reflect such considerations. Current US nuclear forces are not well prepared to provide deterrence against a nuclear Iran.
The deterrent value of US conventional forces is equally uncertain, if only because US policy and posture throughout the region is in flux. To provide sufficient deterrent value, conventional forces must be credibly capable of delivering the kind of punishment that the Iran regime would not wish to suffer. This, inexorably, means that the United States must maintain the perceived ability to remove the Tehran regime from power; limited, punitive conventional strikes are likely to have only a temporary effect. A conventional force capable of deterring Iran not only from the use of nuclear weapons—actual use or by diplomatic intimidation—but also from destabilizing the region or asserting its hegemonic ambitions, must meet the same qualitative, if not quantitative, standards of the Cold War. There must be a sufficient covering force present to reassure allies and limit Iranian influence or aggression by proxies, and there must be sufficient force available in a crisis or open conflict to pose a credible regime-change threat.
A regime-threatening conventional force must be a large force. The question is not whether a full-blown regime-changing campaign like the initial phases of operations Enduring Freedom or Iraqi Freedom is wise or the only method of regime change in Iran, but whether it is a threat needed for assured or credible deterrence. The biggest challenge for a force of such size will be its deployment, which must also be rapid. Again, the Cold War standard of ten divisions deployed from the continental United States within ten days is illustrative of the strategic logic, if not of the precise operational requirement; the threshold test is to move a large force and to move it fast.
Perhaps the greatest uncertainty and a critical element in future deterrence will be the presence of US forces in the Persian Gulf region and the access to air bases, ports, and other facilities that would be needed to close a substantial force. The laborious and lengthy standing-start deployment of Operation Desert Shield will be all but impossible to conduct under the threat from a nuclear Iran. Some significant US presence in Iraq should be regarded as a necessary, but hardly sufficient, element of conventional deterrence. A credible conventional
deterrent posture in Iraq would demand a continued US presence of at least 20,000, to include a significant joint-service headquarters commanded by a three-star general or flag-rank officer; brigade combat teams in northern, southern, and central Iraq; a substantial training element; and a composite Air Force wing. There was discussion in both Baghdad and Washington about renegotiating the status of forces agreement to maintain US forces in Iraq past 2011; however, the president announced in October that the United States will withdraw all US forces by the end of the year. The White House’s decision dramatically fails to meet the threshold test. It is also a clear signal to the Iraqi government of a loss of US commitment and an incentive for the Baghdad government to lean toward Tehran, or in Tehran’s direction, on issues such as aid and comfort to the Assad regime in Syria.
Continued US presence in Kuwait and access to facilities there is equally essential. The US partnership with Kuwait has been solid since the end of the 1991 Gulf War, and the periodic presence of US ground, naval, and air forces, as well as the use of key facilities, has been considered by Kuwaitis as critical to their own security and survival as an independent state. However, this concentration of forces and facilities could become a weakness in a time of conflict, a relatively small and close-range target for Iran and precisely the reason Iran is so interested in antiaccess capabilities.
The story is the same elsewhere through the western reaches of the Persian Gulf and the northern Arabian Sea. Bahrain has long played host to the Navy’s Fifth Fleet headquarters, but not only is this well within range of Iranian forces, but Iran also plays a large role in exacerbating the legitimate grievances of the repressed Shia majority there. Access to and training arrangements with other Gulf Arab states, including Saudi Arabia, will have to be maintained.
Containment and deterrence argue for a strong US and allied posture to the east as well. Just as an enduring US military presence in Iraq is critical for deterring a nuclear Iran, so will it be needed in Afghanistan. To be sure, the principal strategic purpose of a long-term US strategic partnership with the Afghans is driven primarily by the need for internal stability—avoiding a civil war or the restoration of a Taliban-like state—and concerns about Pakistan, but it is nearly as critical if Iran is to be deterred and contained. Iranian influence is traditionally strong in western Afghanistan; conversely, US operations since 2002 have focused on the Kabul region and southern and eastern Afghanistan.
A third facet of a deterrence-and-containment approach would be a strategic and military reengagement across Iran’s north. While Turkey remains an important US ally and Ankara’s own security interests would be deeply affected by a nuclear Iran, the relationship has soured since the heady times of the first Gulf War and the long-running no-fly-zone operations that followed. Moreover, Turkey’s strategic interests have shifted substantially. Beyond the challenges of relations with the United States (and Israel), the frustrations of failure to win European recognition plus the rise and durability of the AK Party have seemed to shift Turkey’s orientation, and, at the moment, it is acting more independently. A nuclear Iran might present the United States with an opportunity to reestablish a closer partnership with Turkey; conversely, even a nonaligned Turkey would be a problem for deterrence and containment. The United States has often been indifferent to the well-disposed states in the Caucasus—Georgia and Azerbaijan—which could provide key outposts in regard to Iran. While the indifference is most often the result of US-Russia policy (the 2008 Georgia war being the obvious example), the effect is also a problem when it comes to Iran. The northern front of a deterrence and containment posture would not demand large forces, but it would require more constant US policy, defense exchanges and cooperation, access to facilities, joint exercises, and the like.
Taken together, a serious policy of containment and strategy of deterrence calls for constant and significant conventional force presence around Iran’s perimeter. Although requiring far fewer forces than in Europe or Asia during the Cold War and far fewer than have been needed to fight the wars in Iraq or Afghanistan, the total might easily approach 80,000. Land and land-based air forces in Iraq, the Gulf, and Afghanistan alone might be 50,000 or more, and maritime forces plus various headquarters and training missions could add another 30,000. Not a huge force, but the need to support, sustain, and rotate units would drive the bottom-line force-structure bill to 350,000 out of the total active force. This force now numbers 1.3 million, but when already enacted budget cuts come fully into effect, it may drop to 1.1 million. Further budget and force cuts would make the overall contain-and-deter posture a disproportionately large one for a reduced force.
The forces needed for reinforcement in times of crisis or conflict are equally difficult to estimate with precision but equally close to the limits of the future US military that would be the result of the budget cuts and force reductions in view. Operationally, a reinforcing deployment of forces would need to meet two very challenging hurdles: the near-immediate initiation of a large-scale strike campaign to destroy, with a high degree of confidence and certitude, Iran’s fielded nuclear capabilities and to control the nuclear facilities, materials, and infrastructure—including the scientists, engineers, and work force that comprise the human infrastructure—to limit the dangers of “loose nukes,” rapid reconstitution by Iran, or proliferation to others.
The nature of a strike campaign against Iranian nuclear facilities has been the source of much speculation and some research in the press and other public domains in recent years.131 There is no quick-and-easy solution, no Osirak-like, one-attack answer. Indeed, the analysis presented on Iran’s nuclear program strongly suggests that Tehran has learned the lessons of Israeli strikes on Iraq and Syria and is pacing its program with an eye toward presenting the world with a robust and survivable nuclear capability. As Meir Dagan, the recently retired head of Israeli intelligence, put it, not only would destroying Iran’s nuclear capability be beyond Israel’s conventional capability, but “it will be followed by a war with Iran. It is the kind of thing where we know how it starts, but not how it will end.”132
What is impossible for the Israeli defense forces would also be extremely challenging for the US military. The first requirement is for rapid deployment and simultaneous attack to diminish the prospects of an Iranian second or retaliatory nuclear strike, aimed at not only the United States or US forces but also others in the region or in Europe. Of course, there can never be a guarantee of getting it all in the first attacks, but unless there is a high degree of confidence in delivering what amounts to a nuclear knock-out blow, the United States rather than Iran will be the deterred party. Such a paralyzing strike would also demand attacks on Iranian military command and control and civilian government targets. It would require a sustained effort. The presumption that a strike campaign would be followed by a war with Iran is the only sound basis for military planning.
Such a strike campaign might easily tax the full range of US capabilities, from long-range bombers and unmanned systems to cruise missiles launched from submarines and surface combatants to thousands of tactical aircraft sorties. Indeed, any sustained campaign, any campaign longer than forty-eight hours, would ultimately rely on tactical aircraft, and the most sophisticated, fifth-generation aircraft, the F-22 and the F-35. Only those platforms can generate the weight and durability, as well as the tactical flexibility, such a campaign would demand. At the same time, it would be impossible to maintain such a campaign absent access to a large number of regional airfields. This cannot be a unilateral US effort if it is to succeed tactically.
A parallel and near-simultaneous effort must be made to secure physically some number of the most important Iranian nuclear facilities. Short of employing a low-yield nuclear weapon, no level of conventional attack can fully destroy these facilities, particularly those that are hardened or buried underground. The need to secure the sites, to prevent a nuclear-related accident, retaliation by unconventional means (as with a dirty bomb made with nucle
ar materials), and to forestall reconstitution or proliferation, will be urgent. This is not a mission that can await postwar UN inspections. There would be an operational imperative to insert relatively small but still substantial, sustainable, and robust forces on the sites in question. They would need to do thorough damage assessment, rapid intelligence exploitation, and fully secure what remains—including the people who remain—all in the midst of a larger war and a hostile Iranian population. This would be extremely challenging, but the strategic and operational logic would be extremely powerful. Failure to secure the most critical attacked sites would make it difficult to end the conflict or to have confidence in any postwar outcome.
The initial strike-and-seize efforts are best thought of as the opening phases of a war, not the sum total of the conflict. There is no way to reestablish peace on the basis of the status quo, and keeping Iran in its box—as was tried with Saddam Hussein’s Iraq—is equally unlikely. Indeed, there might be a lengthy operational pause to build up forces in the region to continue the conflict or to frame negotiations, but the object should be regime change in Tehran. How could a US government, its regional allies, or the rest of the world contemplate leaving the revolutionary regime in power under such circumstances? It would be preferable to achieve regime change in negotiation with Iranians; invading Iran or conducting postwar stability operations would be extremely unpalatable and probably more difficult than in Iraq or Afghanistan. As has been apparent, there is deep opposition within Iran to the current regime, but the credible threat of regime change by force would be a precondition to achieving the result with less bloodshed.
The size and composition of a force capable of credible regime-change, even supposing that prior seize-and-strike efforts have been successful, can be imagined only in the most general, qualitative terms. It must be large, both as measured by firepower and troop strength. The credible threat will be based upon the perceptions of the Iranian leadership that it faces an imminent air-land invasion. And, of course, it must have been deployed in a timely fashion, including deployed by sea; there is no way to get the bulk of the materiel to the theater any other way. Prepositioned stocks will be necessary but are likely to have been composed for and consumed by the strike campaign. Again, any worthwhile analysis of the requirements for a decisive, regime-changing air-land campaign is beyond the scope of this study.
It helps to recall the size and scope of operations Desert Shield and Desert Storm; an invasion of Iran or a credible threat of invasion would be a contest more akin to the 1991 war than the 2003 blitz to Baghdad, a maneuver than had been in preparation for a decade. In the first Gulf War, the United States deployed more than 1,300 tactical fighters and strike aircraft, 285 tankers, 175 airlifters, and more than 200 other support planes for a total of just under 2,000; most of these were land-based aircraft, but carrier air played a significant role. In addition, coalition partners contributed more than 500 other aircraft, most usefully and notably 276 Saudi strike and fighter planes.133 The Army deployed two
full corps of seven divisions and two cavalry regiments, and the Marines deployed a corps-sized expeditionary force that got a good deal of its heavy punch from an attached Army armored brigade.134 The Navy surged a six-carrier fleet plus dozens of surface combatants capable of firing Tomahawk cruise missiles; it also feigned an amphibious landing that tied down large Iraqi formations on the coast of Kuwait.135
This is not to say that a credible Iran deterrent force would be identical; it is simply to provide an order-of-magnitude benchmark. Generating such a force may be beyond the capabilities of the future US military, at least if current budget trends are not reversed. The active-duty Army is on course to shrink to 400,000 soldiers; 500,000 soldiers were deployed to Southwest Asia for Desert Storm. The US Air Force is on course for about 1,200 total tactical aircraft, the Navy for eight carrier battle groups and thirty-three attack submarines. In the aftermath of a recent strategic defense review, the British army retains a single armored brigade.136
Comparisons to the Desert Storm era are illustrative and nothing more. The question that needs analysis is what kind of force is operationally capable of conducting a regime-change campaign in Iran and, more to the point, what kind of threat would be understood by Iranians as a credible deterrent. What ought to be obvious is that current US defense planning is entirely devoid of such analysis and thus the military posture required for containment and deterrence cannot be assumed.
In both nuclear and conventional realms, the United States and its containment-coalition partners are likely to lack the military means to make a deterrent posture credible either to the Iranians or to ourselves. This reprises a recurring Cold War lesson: empty attempts at containment and deterrence are not just half-answers but positive incentives to an adversary predisposed to discover weakness, ambitious for power, and regarding itself with a historic destiny.