Overthrowing Saddam: Calculating the Costs and Casualties

This is the first Memo in a series of analyses on the Iraq Crisis from The Saban Center for Middle East Policy at the Brookings Institution.

For many Americans, a critical concern about war with Iraq is the question of cost, both in terms of lives lost and tax-payers’ money spent. It is always difficult to predict beforehand the number of casualties a war will produce, or how many dollars it will consume. This is even more difficult without access to either classified assessments of enemy capabilities or the military’s intended plans. Nevertheless, history can often provide some guidance in grappling with these important unknowns.

In regard to casualties, the experience of trying to forecast Desert Storm is chastening for those who believe that precise predictions are possible, but some general parameters can still be established. In particular, the United States could plausibly lose anywhere from about 100 soldiers, should the Iraqi military crumble or overthrow Saddam once American forces are perched on their border, to as many as 5,000 troops if the Republican Guard fights as hard and as effectively as its size and weaponry would plausibly allow within the urban settings of Baghdad and other Iraqi cities. In other words, while such a war would not become a quagmire under even the worst of circumstances, it could be rather bloody. Moreover, Iraqi civilian casualties could be ten times as great as U.S. losses, generating strong opposition from international public opinion, particularly in the Arab street. This is yet one more reason to make any such war quick and decisive through the use of overwhelming force.

An invasion to overthrow Saddam Hussein would likely cost the United States about $50 billion, though it could plausibly range from $25 billion to $75 billion or so, with likely annual U.S. costs of maintaining order in Iraq ranging from $5 billion to $20 billion for a number of years thereafter. The latter costs of winning the peace, and associated wear and tear on American military personnel, may actually turn out to be a greater concern than the one-time cost of winning the war.

Estimating Casualties

Consistent with military and strategic logic, and with leaked Pentagon war plans from the summer of 2002, this article assumes that a war to overthrow Saddam would involve about 250,000 American forces. Relying on small numbers of U.S. special forces and American airpower to aid indigenous opposition groups fighting government forces—as we did in Afghanistan—almost surely would not work in Iraq. The weakness of the Iraqi opposition and the Iraqi military’s ability to hole up in cities, where American airpower is far less effective than in open terrain, makes this option non-viable. Modest-sized operations, involving perhaps 50,000 to 75,000 U.S. troops, are somewhat more promising. But they would run the risk of encountering serious difficulties in the urban centers of Iraq. Iraqi forces would also be less likely to capitulate quickly if they sensed they had a chance to prevail, increasing the chances of a prolonged urban battle under such circumstances. This is not to say that a larger operation would have to mirror Desert Storm in its basic concept. The invasion might involve certain “inside-out” tactics such as rapid airborne or commando strikes against Iraqi command and control assets as well as weapons of mass destruction sites in the earliest hours of combat, even as main invasion forces march more slowly through Iraq towards Baghdad and other cities. But that does not obviate the need for a powerful invasion force to make sure the job is done quickly and decisively, through brute strength if necessary.

Two recent conflicts may provide better indicators of the likely nature of a future U.S.-Iraq war: the 1989 invasion of Panama and the 1993 U.S. experience in Mogadishu, Somalia. In December, 1989, it took 22,500 U.S. troops to overthrow Panamanian strongman Manuel Noriega and defeat his armed forces. The massive, simultaneous assault overwhelmed Panama’s 4,400-strong defense forces, surprising them with its ferocity and coordination in the opening hours of battle. Twenty-three Americans died, as did about 125 Panamanian military personnel. Perhaps 200 to 600 Panamanian civilians died as well.

In the Somalia experience, U.S. forces faced ragtag militia opposition. Somali fighters had access to plentiful automatic weapons, rocket-propelled grenades, and mines, but not much more than that, and they were not trained in combined-arms or coordinated military operations. Only about 2,000 U.S. forces were deployed for conducting and supporting such raids at the time they occurred; only 160 participated in the October raid. Total losses reached 29 from hostile action and 14 from “non-hostile” action, such as accidents. Estimates of Somali militia strength were in the many thousands, with losses on October 3-4 alone estimated at 300 or more combatants.

Simply scaling the results of Panama for the size of the Iraqi military leads to an estimate of about 2,000 killed Americans, more than 10,000 dead Iraqi military personnel, and tens of thousands of dead Iraqi citizens. If however it is only the elite Iraqi forces that fight hard, numbering somewhat more than 100,000 Republican Guard, Special Republican Guard, and palace guard forces, extrapolation from the Panama case suggests that losses on all sides might be only one-fourth as great. The Somalia analogy is also worth invoking. The firefight on the night of October 3-4 can be used as a way to generate pessimistic estimates of how war in Baghdad might go. As noted, that operation involved about 160 Americans against a single objective, together with roughly a dozen ground vehicles, and more than a dozen helicopters. Overall operations in Baghdad might be 50 to 100 times as large, in any initial assault wave to secure key facilities. With comparable casualty rates on a per person basis, U.S. losses could number 1,000 or more just in this first phase of the fighting.

Scaling from previous conflicts, Iraqi troop losses might be expected to be as many as 50,000, though in the event of a quick defeat they might number far less. And Iraqi civilian deaths could number in the tens of thousands as well. Even careful bombing by the United States would produce large numbers of civilian casualties, given Saddam?s likely decision to hole up in cities, using civilian populations as shields for his military forces.

One major wild card remains: the likely consequences of any Iraqi use of weapons of mass destruction on the battlefield (Iraqi attacks against more distant targets using special agents or SCUD missiles are not considered here, though the latter at least seem a relatively modest military threat). If it used chemical or biological agents against invading forces, Iraq might increase their casualties by 10 to 20 percent, given historical precedent in conflicts such as the Iran-Iraq war, though U.S. forces might suffer fewer losses given their protective gear and other defensive capabilities. However, by using such agents even occasionally, Iraq could oblige coalition forces to fight in protective gear, slowing operations and generally complicating the mission. If the effects of fighting in such gear were comparable to those of fighting in bad weather or difficult terrain, for example, the pace of coalition fighting and the effectiveness of coalition forces might decline 25 to 50 percent, and casualties might mount by a comparable percentage. As a last resort, Saddam might also unleash biological or chemical agents on Iraqi Kurds and Shias to generate massive refugee flows. This would obviously drive up the Iraqi casualties, perhaps by many thousands, and could slow down our operations considerably.

Budgetary Costs

How much would it cost to win a war to overthrow Saddam? In 1991, a mission involving some 550,000 U.S. forces in a 40-day desert war cost about $80 billion in today’s dollars (almost all of which was reimbursed to the United States by regional allies as well as Germany and Japan). In rough terms, those costs included $10 billion for deployment, $20 billion for personnel, $30 billion for operating and fuel costs, $10 billion in investment of hardware (largely to replace consumed ordnance), and a few billion dollars in other costs. Simply scaling that number downward to reflect a mission likely to be about half as large, but perhaps somewhat more intense, leads to a ballpark figure of $50 billion. Assuming occupation forces might involve 10,000 to 40,000 Americans at first, annual costs might be anywhere from roughly $5 billion to $15 billion or more thereafter, by analogy with the per person costs of recent stabilization operations in the Balkans.

The House Budget Committee and Congressional Budget Office have recently provided finer-tuned estimates of war costs that back up these rough figures fairly well. The House Budget Committee, arguing largely by analogy with Desert Storm and its above categories of expense, estimates a rough cost of $50 billion to $60 billion for a 250,000-strong operation lasting one to two months, and $35 billion to $40 billion for a mission half that size.

The Congressional Budget Office subsequently made estimates for a war involving 250,000 to 350,000 forces in the Persian Gulf theater, including possible ground force strength of roughly 3-6 divisions and 11-16 tactical fighter wings (including Marine and carrier-based varieties). Assuming one-to-two months of combat, the smaller force option was estimated to cost about $20-30 billion, and its larger option $30-40 billion. The CBO estimates seem rather low by comparison with the Desert Storm experience, not to mention the expected complexities of urban combat.

Either way, the really striking point about these estimates are twofold. First, given the expected quick pace of any war, these estimated combat costs are large but hardly astronomical, whether one compares the cost of past wars, the peacetime U.S. defense budget ($400 billion) or the U.S. GDP (well over $10 trillion, meaning war costs would almost surely be under 1 percent). Second, however, occupation costs could be substantial; CBO estimates a cost of $15 billion to $45 billion a year for a force of 75,000 to 200,000. It seems unlikely that U.S. forces would be deployed in such high numbers for long, but without major allied support that is at least a remote possibility. More plausibly, occupation costs might be in the broad range of $10 billion a year, roughly comparable to what the United States spends on its global development assistance and humanitarian relief efforts.