Since the end of the Cold War, America’s role in the world has been dominated by small-to-medium scale military strikes and deployments in numerous hotspots around the globe. The justification for each intervention is often debated in human costs, geopolitical outcomes, and foreign policy paradigms. However, there are many other costs of military intervention, including unseen fiscal costs and unintended consequences of action.


Pure Military Costs

In order to conduct a military strike, the Pentagon requires three main asset categories:

  • Missiles and munitions to hit intended targets (Tomahawk missiles) (TLAM)
  • Enabling vessels from which to launch (submarines, ships, aircraft, etc.)
  • Personnel to operate the attack (active sailors)

When an American President authorizes a strike and it is carried out, the actual costs of the action are very low. That’s because the United States has already purchased the equipment and manpower needed. When looking at a potential strike in Syria in 2013, for example, Gordon Adams of American University said that “we already bought the five destroyers now off the Syrian coast… and the Tomahawks the president plans to fire off, if he gets the vote he wants, years ago… and we are paying the sailors who will fire them off.”


Because the main instruments of a strike are already paid for by the Pentagon and in place, pure military costs typically come from refueling, potential extra hazardous duty pay, and hardware replacement. In the same Syria example, Adams totaled these costs at no more than $500 million. For comparison, Operation Desert Strike in Iraq, a four-day bombing campaign in 1998 that took place without any American casualties was also estimated to cost $500 million.


The majority of expenses in these types of attacks comes from restocking equipment and moving beyond routine operations. One Tomahawk missile costs about $1.5 million, so replacing hundreds of them costs several hundred million dollars. According to the Navy, strike carriers already in the Mediterranean cost $25 million a week on a routine course. If aircrafts are engaged in special combat-related flights the cost rises to $40 million. These modifications alone would not create a huge dent in an annual defense budget of $500 billion.


In recent years, presidents typically have asserted that military operations will be narrow in scope and limited in how many targets are attacked. However, the unfortunate reality has been that military costs rarely happen in isolation, and must be considered together with likely humanitarian support and additional military action based on enemy retaliation, not to mention the costs associated with training local military and stabilization.


That’s part of why recent estimates suggest the cost of defeating ISIS/ISIL militarily could reach upwards of $200 and $320 million per month — or even possibly over $1.5 billion per month.


The Forgotten Costs of Intervention

The most significant variable in evaluating future costs of intervention is unpredictability in, or the potential for, America’s role to expand. This can happen during mission creep, where the goalposts keep moving with tactics and strategy shifting to fit ever-evolving objectives. Obvious cases are Somalia and the Second Gulf War.


Another problem is when the scale of an limited operation increases such that more assets and resources need to be devoted to the conflict. The 2009 surge in Afghanistan is a recent example where the mission stayed the same but more force than originally intended was deemed necessary.


Many unforeseen issues can arise, exacerbating costs enormously:


1. Prolonged conflict
Limited military strikes that do not evolve into full-scale or longer-term conflicts are rare. After the initial bombardment, it is possible — or likely — for regional developments to occur that would necessitate a longer duration or heightened degree of action. In Syria in 2013, some wanted a short strike that punished the regime for using chemical weapons; in 2014, the U.S. mission had evolved to short strikes that sought to root out ISIS. Escalation of the conflict, though, is likely to follow, as a strike could be seen as an act of war or further escalate tensions in the region at large. More extensive training of the rebels, implementing a no-fly zone, or creating buffer zones would all increase costs. Once the first missile launches, the U.S. would practically need to be prepared to fund any necessary follow up action.


2. Capable Defenses
Historically, the United States has lost few if any human casualties during limited interventions. Our technological and tactical superiority is unrivaled in most of the countries we have attacked (Somalia, Afghanistan, Libya). In contrast, some countries (like Syria) have larger, better-equipped, trained, and armed forces. Attacking a country with a capacity to defend itself is far different from previous scenarios. Should America lose aircraft or receive damage during a strike on such a country, we would face much higher human and financial costs.


3. Retaliation on America or Allies

There is also the possibility that the target country can withstand a strike and respond with a counter-attack after. In the case of Syria, for example, capable allies in the region from Iran to Hezbollah could carry out retaliation against America abroad or at home. Such responses could also be directed at regional allies such as Turkey and Israel or even to more distant countries in Europe. Retaliatory attacks mean loss of equipment, higher restocking rates, more security for vulnerable targets, and increased U.S. involvement. The degree to which the United States could be pulled into another war is not entirely in the country’s control and would demand military expenditures much larger than initial estimates.


4. Cost of Neglecting other Policy Issues

From an economic perspective, the opportunity cost of intervening in any conflict is significant. The United States would sacrifice public attention and resources to focus on foreign policy instead of critical domestic issues. Conditions would be made more difficult for passing meaningful domestic reforms and controlling the debt during the inevitable fiscal fights.


5. Future Veteran Costs for an Extended Conflict

If an escalation conflict arises and “boots on the ground” become a reality, unfunded expenses on future benefits for these soldiers would increase. Taking care of wounded veterans, extra medical or disability care, and education benefits raise long-term costs. Analysts may not be able to predict if a given strike would escalate, but support to veterans who survive the conflict would also be a necessity.


6. Humanitarian Relief

Military interventions in the past have almost always included a humanitarian support element, and these efforts raise significant costs. Paying for sanctuaries and buffer zones for refugees or displaced people consumes defense and civilian resources. Establishing safe zones, protecting them, feeding and housing people, and providing medical aid increases expenditures. Other humanitarian efforts such as airlifts and evacuations exacerbate costs. In FY2013, for example, the United States provided over $1 billion of humanitarian assistance and more than $250 million in non-humanitarian aid to the people of Syria to support the opposition.


The above examples are only some of the ways in which interventions produce hidden costs or consequences that would demand more American resources. Of course, these options don’t even begin to cover the foreign policy objectives and diplomatic hurdles that would go on simultaneously.


Sources of Funding

While the scope and focus of an intervention are important to evaluating potential costs, how these interventions are funded is just as critical. For perspective, the Pentagon’s base budget for FY 2014 was $526 billion with an additional Overseas Contingency Operation (OCO) account request of 88.5 billion. New military interventions or engagements would require funds from the current fiscal year, the next fiscal year, supplemental appropriations, or all three sources.1


Depending on the timing and scope of a given operation, current year and next year monies could be available. This means that funds from the base budget or OCO could be dedicated without any new costs to the Pentagon. However, supplemental appropriations requested from Congress have proven the norm if and when interventions need more funding.


In most cases, the Pentagon and the President can find available money in the base or OCO budget by moving appropriations between accounts. Through reprogramming, critical need operations will take priority over previously dedicated activities.  According to the Congressional Research Service, the brief U.S. military operations to establish a no-fly zone in Libya relied almost exclusively on existing appropriations. In fact, “there is no restriction that prevents the President from using available funds to conduct wartime operations.” This flexibility allows the Pentagon to address national security issues as they come up, which is handy when a crisis emerges. However, the Overseas Contingency Budget should be reformed to ensure that it is being used as intended, not as a “slush fund” as critics have suggested.


Military interventions typically start off relatively inexpensively and come from the current OCO or base budget, and in these cases, the impact on national levels of spending is small. However, as the largest and fastest growing portion of federal discretionary spending, there is a problem of ever-increasing Pentagon commitments. Should interventions escalate, more money would be needed to restock missiles and other expenses. As the United States continues to borrow to fund ongoing annual deficits, any new significant spending by the Pentagon directly flows through to the national debt.


1 Blanchard and Sharp. Ibid.