The True Cost of Ending ISIS
What would be the true cost of definitively defeating the Islamic State in Iraq and Syria (ISIS)? The answer should properly be measured in trillions of dollars, not $500 million per month for a no fly zone or the $330 million per month the United States is currently dispensing. It is increasingly clear that air power alone is insufficient either to defeat ISIS or to ensure the necessary post-conflict stability to prevent the rise of a similar terrorist threat in the region. Large numbers of ground troops—more than a token number of American Special Forces—would be required to achieve this goal.
Despite the recent announcement of an “Islamic military alliance against ISIS” headed by Saudi Arabia and the recent success of the Iraqi army in pushing ISIS out of the city of Ramadi, it is unlikely that the United States would be able to wholly outsource ground operations to local partners. Saudi Arabia is already engaged in an inconclusive military intervention in Yemen and the nascent alliance likely lacks both the political will for a long-term deployment and sufficient numbers of ground troops to pull it off. When the Iraqi army pivots north to the much larger city of Mosul, the potential for civilian casualties increases and the U.S.-led coalition will not be able to use airpower with as much impunity. Even if Kurdish forces were able to roll back ISIS on their own, the political costs for Turkey and the central Iraqi government would be far too high for either of them to support such a plan regardless of U.S. preferences.
The closest point of comparison for a comprehensive military campaign to destroy ISIS is the U.S. invasion and occupation of Iraq, which cost approximately $900 billion. There are two important considerations to keep in mind, however, when comparing the potential costs of defeating ISIS to past actions in Iraq. First, the cost of major operations in Iraq from 2003-2011 bought failure—in so far as it set the preconditions that allowed ISIS to form in the first place. Costs would likely be higher, therefore, if the U.S. sought to not only defeat ISIS once and for all but also to fully reconstruct Iraq and Syria and provide the necessary assistance to other regional states to prevent the rise of Islamist terrorism in those areas. (As Andrew Bowen has noted, ISIS’s “brand represents a broader long-term challenge than the actual ‘state.’”)
Secondly, the cost of operations in Iraq (averaging less than 1 percent of U.S. gross domestic product) is actually quite small relative to past invasion and reconstruction efforts. According to estimates by John A. Thompson of the University of Cambridge in a recent history of American foreign policy, the United States spent a full 7 percent of its gross national product (GNP) on defense during the early days of the Korean War, and a much higher percentage, up to 42 percent of GNP, during World War II. The Marshall plan, money earmarked for the reconstruction of Europe following World War II, cost 1.2 percent of GNP in 1947.
It follows, then, that to fully defeat ISIS and prevent the rise of another terrorist organization would require expenditures at similar levels, totaling trillions of dollars, not billions or millions. The equivalent of a Marshall plan for the Middle East—reconstruction efforts only—would cost nearly $200 billion. Were the United States to finance its military at the equivalent of early Korean War levels, it would cost $1.16 trillion per year. Even subtracting the Pentagon’s current base budget of $585 billion leaves over $500 billion in direct war costs alone.
The United States is simply not going to spend in excess of $1 trillion per year in order to wage war against ISIS and rebuild the Middle East. This is clearly for the best. Despite the demonstrated shortfalls of President Obama’s strategy, ISIS has lost as much as 40 percent of its territory in recent months and many of its most visible leaders. Spending so much money on military action—even if it actually could defeat ISIS, fundamentally transform the Middle East and eliminate the threat of Islamist terrorism write large—also means that it cannot be spent on more productive activities at home.