The use of military force has been a difficult subject for American leaders for three decades. Ever since the failure of American policy and military power in Vietnam, it has been hard for U.S. policy makers to gain domestic support for the use of force as an instrument of statecraft. U.S. military power has been exercised throughout this 30-year period, but both threats of its use and the actual conduct of military operations have usually been controversial, turned to reluctantly, and marked by significant failures as well as successes. The American armed forces are large, superbly trained, fully prepared, and technologically advanced. Since the demise of the Soviet Union, U.S. forces are without question the most powerful-by far-on the face of the earth. Their competence, lethality, and global reach have been demonstrated time and again. Yet with rare exceptions, U.S. policy makers have found it difficult to achieve their objectives by threats alone. Often, they have had to use force-even if only in limited ways-to add strength to the words of diplomats. And, at more times than is desirable, the failures of threats and limited demonstrative uses of military power have confronted U.S. presidents with difficult choices between retreat and “all-out” military actions intended to achieve objectives by the force of arms alone.
In the 1980s most U.S. military leaders and many politicians and policy makers drew a strong conclusion from the failure of U.S. policy in Vietnam. This viewpoint was spelled out most clearly by then Secretary of Defense Caspar Weinberger in 1984: force should only be used as a last resort, he stated, to protect vital American interests, and with a commitment to win. Threats of force should not be used as part of diplomacy. They should be used only when diplomacy fails and, even then, only when the objective is clear and attracts the support of the American public and the Congress.
General Colin Powell, former chairman of the Joint Chiefs of Staff, was and remains a proponent of what was called the Weinberger doctrine. “Threats of military force will work,” he says, “only when U.S. leaders actually have decided that they are prepared to use force.” In the absence of such resolution, U.S. threats lack credibility because of the transparency of the American policy-making process. For this reason “the threat and use of force must be a last resort and must be used decisively.” Powell (1992a, 1992b) has argued that any use of force bythe United States should accomplish U.S. objectives quickly while minimizing the risks to U.S. soldiers.
Other U.S. policy makers have taken a more traditional geopolitical view, believing that the U.S. failure in Vietnam needs to be understood on its own terms. Regardless of what was or was not achieved in Southeast Asia in the late 1960s and early 1970s, the United States, they believe, can and should continue to threaten and to use limited military force in support of diplomacy, to achieve limited ends without resorting to all-out contests of arms. In the words of then Secretary of State George Shultz in December 1984, “Diplomacy not backed by strength will always be ineffectual at best, dangerous at worst” (Shultz, 1985). Moreover, Shultz insisted, a use of force need not enjoy public support when first announced; it will acquire that support if the action is consonant with America’s interests and moral values. In 1992 Les Aspin, then chairman of the House Armed Services Committee and later secretary of defense, branded the Weinberger doctrine an “all-or-nothing” approach. He asserted that the United States should be willing to use limited force for limited objectives and that it could pull back from such limited engagements without risk. From this perspective, force should be used earlier in a crisis, rather than later, and need not be displayed in decisive quantities. The “limited objectives” school describes the threat of force as an important and relatively inexpensive adjunct to American diplomatic suasion.
As the Soviet Union disintegrated and the Cold War came to an end, this debate began to wane. U.S. policy makers began to wrestle with an array of problems that were individually less severe than the threat posed by the USSR but collectively no less vexing. The military situation changed drastically as well. U.S. military power reigned supreme, and the risk that a limited military intervention in a third nation could escalate into a global confrontation quickly faded. During both the Bush and first Clinton administrations, it became increasingly evident not only that there were many situations in which limited applications of force seemed helpful but that in the complicated post-Cold War world, opportunities for the pure application of Secretary Weinberger’s maxims were rare. During this eight-year period, numerous challenges to American interests emerged that were too intractable for diplomatic solutions, that resisted cooperative multilateral approaches, and that were immune not only to sweet reason but to positive blandishments of any sort. Unencumbered by Cold War fears of sparking a confrontation with the powerful Soviet Union, American policy makers turned frequently to threats and the use of military power to deal with these situations, sometimes in ways that conformed to the Weinberger guidelines but more often suggesting that-rightly or wrongly-‘ the press of world events drives policy makers inevitably toward Secretary Shultz’s prescriptions for limited uses of force in support of diplomacy.
The United States sometimes succeeded in these ventures and sometimes failed. Success rarely came easily, however; more often, the United States had to go to great lengths to persuade adversaries to yield to its will. Even leaders of seemingly hapless nations, or of factions within devastated countries, proved surprisingly resistant to American threats. Often, U.S. leaders had to make good on threats by exercising U.S. military power. These further steps usually worked-but even when the United States conducted military operations in support of its post Cold War policies the results were not always as clean and easy, or their consequences as far reaching, as decision makers had hoped. Given the overwhelming superiority of U.S. military power during this period, these results are hard to understand.
Indeed, even the greatest military success of the U.S. armed forces in the post-Cold War period-the expulsion of the Iraqi occupation army from Kuwait in 1991-became necessary because U.S. diplomacy, including powerful threats of force, failed. Despite the most amazing demonstration of U.S. military capabilities and willingness to utilize force if necessary to expel the Iraqi military from Kuwait, despite the movement of one-half million U.S. soldiers, sailors, and air men and women to the region, the call-up of U.S. reserve forces, the forging of a global military alliance, even the conduct of a devastating air campaign against the Iraqi occupation army and against strategic targets throughout Iraq itself, Saddam Hussein refused to comply with U.S. demands and his troops had to be expelled by force of arms. The United States was not able to accomplish its goals through threats alone. The Iraqi leader either disbelieved the U.S. threats, discounted U.S. military capabilities, or was willing to withstand defeat in Kuwait in pursuit of grander design.
Why was this the case? Why has it been so difficult for the United States to realize its objectives through threats of using military force alone? Why have U.S. military threats not had greater impact in the post-Cold War period, and why have limited uses of force, in support of diplomacy and in pursuit of political aims, not been able to accomplish U.S. goals more often? Is this situation changing as it becomes indisputably clear that the United States is the only remaining military superpower? Or have history and circumstance made U.S. military superiority an asset of only narrow utility in advancing the nation’s interests through diplomacy?
To answer these questions, we examined all the cases during the Bush and first Clinton administrations in which the United States utilized its armed forces demonstratively in support of political objectives in specific situations. There are eight such cases, several of which include multiple uses of force. In two of the cases, Iraq and Bosnia, threats or uses of force became enduring elements in defining the limits of the relationship between the United States and its adversary.
Actually, the U.S. armed forces have been used demonstratively in support of diplomatic objectives in literally more than a thousand incidents during this period, ranging from major humanitarian operations to joint exercises with the armed forces of friendly nations to minor logistical operations in support of the United Nations (UN) or other multinational or national organizations. Moreover, the deployment and operations of U.S. forces in Europe, and in Southwest and East Asia on a continuing basis throughout the period, are intended to support U.S. foreign policy by deterring foreign leaders from pursuing hostile aims and by reassuring friends and allies. In some cases the presence of these forces, combined with the words of American leaders, may have been sufficient to deter unwanted initiatives. The presence of U.S. troops in South Korea, for example, is believed to deter a North Korean attack. We did not look at such cases of continuing military support of diplomacy in which “dogs may not have barked.” Instead, we looked only at the handful of specific incidents in which U.S. armed forces were used deliberately and actively to threaten or to conduct limited military operations in support of American policy objectives in specific situations.
We did not examine such military threats prior to the Bush administration, because, as noted above, the Cold War placed significant constraints on U.S. uses of force. We believe that the demise of the USSR altered the global political and military environments so fundamentally as to make prior incidents irrelevant to understanding the effectiveness of contemporary military threats. The puzzle we seek to explain is the frequent inability of the United States to achieve its objectives through threats and limited uses of military power despite the political and military dominance it has enjoyed since 1989.
We supplemented published information about the cases we considered with interviews with key U.S. policy makers during this period, including individuals who served in high positions in the Pentagon and at the State Department. At times these individuals are quoted directly. More often, their perspectives provide background and detail in the accounts of the incidents.
We have concluded that the U.S. experience in Vietnam and subsequent incidents during both the Carter and first Reagan administrations left a heavy burden on future American policy makers. There is a generation of political leaders throughout the world whose basic perception of U.S. military power and political will is one of weakness, who enter any situation with a fundamental belief that the United States can be defeated or driven away. This point of view was expressed explicitly and concisely by Mohamed Farah Aideed, leader of a key Somali faction, to Ambassador Robert Oakley, U.S. special envoy to Somalia, during the disastrous U.S. involvement there in 1993-1995: “We have studied Vietnam and Lebanon and know how to get rid of Americans, by killing them so that public opinion will put an end to things.”
Aideed, of course, was proven to be correct. And the withdrawal from Mogadishu not only was a humiliating defeat for the United States but it also reinforced perceptions of America’s lack of resolve and further complicated U.S. efforts to achieve its goals through threats of force alone.
This initial judgment, this basic “default setting” conditioning foreign leaders to believe that U.S. military power can be withstood, has made it extremely difficult for the United States to achieve its objectives without actually conducting military operations, despite its overwhelming military superiority. With the targets of U.S. diplomacy predisposed to disbelieve American threats, and to believe they can ride out any American military initiative and drive away American forces, it has been necessary for the United States in many incidents to go to great lengths to change these individuals’ minds. Reaching this defining moment-the point at which a foreign decision maker comes to the realization that, despite what may have happened in the past, in the current situation US. leaders are committed and, if necessary, will persevere in carrying out violent military actions-has become a difficult challenge in US. diplomacy. It also creates a large obstacle to resolving conflicts and protecting U.S. interests while avoiding military confrontation