Revisiting the Power of American Deterrence

Revisiting the Power of American Deterrence
Story Stream
recent articles

President Obama announced on Tuesday that the international community and Iran had struck a 10-year deal to curb Iran’s nuclear program. Reaction in the United States has been mixed. Some view the deal as a positive step toward normalizing US-Iran relations—bringing the Middle East back from the brink of large-scale nuclear proliferation—while others see the Obama administration’s deal as a fool’s errand. In the end, time will tell who is right.

One thing that is already clear about the future, however, is that deterrence will remain a pivotal goal of U.S. strategy toward Iran and other potential foes. Because the costs of armed conflict against these adversaries are high, policymakers will look for ways to protect American interests without engaging in open warfare. In this context, it is useful to step back and take a larger look at deterrence and how it works.

The essence of the concept of deterrence can be found in the word itself; the root of “deterrence” is the Latin deterre, which means to frighten away. The Department of Defense defines deterrence in similar, yet more specific, terms as “The prevention from action by fear of the consequences. Deterrence is a state of mind brought about by the existence of a credible threat of unacceptable counteraction.” Simply put, deterrence occurs when one can make an adversary believe that the consequences of behaving undesirably will outweigh the benefits.

Deterrence has most frequently been explored through the lens of the Cold War, when the promise of massive nuclear retaliation kept the world from plunging into global thermonuclear warfare. Yet the concept of deterrence encompasses a much broader range of human behaviors, and existed long before the advent of nuclear weapons or the countries that wield them.

In fact, the logic underlying deterrence has been around for centuries. During the Peloponnesian Wars in ancient Greece, for example, Sparta threatened to launch an invasion of Attica if Athens carried out an attack against Potidaea. The long peace between Rome and its rival Persia in the fifth century AD was not due to a lack of potential for conflict, but rather because certain strategic and economic conditions made successful deterrence possible.

Efforts to deter undesirable actions by others take place at all levels of government, in business, education, and our interactions with others. One can find examples in virtually every aspect of human interactions. For instance, drivers often see signs that read “Fines Doubled” near construction zones. If it were the desire of the highway patrol to collect the most fines possible, they would not warn drivers of the situation. By visibly raising the consequences of speeding in a dangerous area the authorities are deterring drivers from behaving in undesirable ways.

Yet as history has shown, deterrence often fails; adversaries attack and drivers run red lights. So what separates deterrence successes from these failures? The key is to establish the credibility of deterrent threats. That is to say, one must be able to instill a sincere belief in adversaries that the promise of counteraction will be carried out if they fail to comply with the threat.

Making a deterrent threat seem credible, however, is often easier said than done. Adversaries may doubt the willingness of an actor to carry out a threat, especially when doing so is costly or risky. Adversaries may also question the ability of an actor to create consequences that are sufficiently harsh. In general, threats to defend one’s own borders—“direct deterrence”—are deemed to be more inherently credible than promises to defend allies in “extended deterrence.” It is easier to promise to sacrifice blood and treasure in defense of yourself than in defense of others.

Concerns about credibility are manifest in the actions that governments take to establish it. In large part, these strategies are consistent with advice provided by the Roman strategist Vegetius, who wrote, “Si vis pacem, para belum”; if you desire peace, prepare for war.

His premise was simple. A powerful military would have a greater chance of deterring an adversary from taking an undesirable action than a weaker military, because a stronger military could more easily punish a potential aggressor. Vegetius’ point is no less valid today than it was almost 2,000 years ago. The United States, for example, develops powerful weapons like tanks, aircraft carriers, and fighter aircraft not in the hope that it will have an opportunity to use them, but rather in the hope that their visible existence will deter adversaries from threatening our interests.

Countries can also increase the credibility of threats by placing their forces at an enhanced state of readiness or deploying them to forward locations. This type of strategy was clearly used during the Cold War, when the United States maintained a large military force in Western Europe to deter a Soviet invasion.

Such actions establish credibility in two primary ways. First, making military forces ready for war increases the likelihood of victory if deterrence fails, and therefore makes it more likely that deterrence can succeed. Adversaries are less likely to pick fights they will lose. Unfortunately, tight budgets and two long wars have hurt America’s military to the point where General Ray Odierno, the Army Chief of Staff, warned in April that the U.S. Army was only at 33 percent readiness. In order to deter Iran and other adversaries through military means, the United States must maintain the ability to fight and win if necessary.

Second, military mobilizations are costly. Because only resolved governments would be willing to pay such costs, deploying or readying military forces helps to signal a country’s commitment to defend itself or its allies. In this light, the potential “Carrier Gap” in the Persian Gulf is concerning to the extent that the lack of a permanent carrier presence may lead policymakers in Tehran to doubt the United States’ willingness and ability to counter their moves in the region.


Today, the United States finds itself in untested waters not only in its relationship with Iran, but also with a resurgent Russia and an increasingly assertive China. Despite these strategic concerns, Washington is faced with serious budgetary constraints that will force policymakers to choose among competing priorities for spending at home and abroad. It is worth noting that deterrence is by no means cheap. However, it is certainly less expensive than war, which creates a dilemma for politicians faced with ever expending demands for social welfare spending.

While considering these imperatives, it is important to remember that when the capabilities and readiness that underpin deterrence are cut, the risks and costs associated with deterrence failure are more likely to be realized. The study of deterrence reveals that preparing to fight against adversaries will help to ensure that conflicts—and their truly unfortunate consequences—never actually occur.

Thus, as Congress debates how to respond to the deal struck with Iran, it is important to remember that American deterrence—in all of its many forms—remains an important part of the equation.  

Show commentsHide Comments