Research Brief

On March 24, 1999, NATO initiated Operation Allied Force as a means to compel Slobodan Milosevic to cease ethnic cleansing in Kosovo and to pull Serbian forces out of the disputed province. Although initially expected to last a few days, the operation did not conclude until June 10, 1999—78 days later—when Milosevic agreed to NATO's terms. Operation Allied Force marked a watershed in the Alliance's history and a significant departure from NATO's exclusive Cold-War focus on the defense of its members' borders. As demonstrated in the Kosovo campaign, the Alliance's new missions can involve crisis response and crisis management throughout Europe, including countries outside the NATO treaty area. In Operation Allied Force, the Alliance showed itself capable of acting when challenged even in circumstances where the territorial integrity and sovereignty of NATO's members was not directly affected.

But what lessons can Operation Allied Force offer to the United States and Europe in preparing for future coalition operations? This question is the focus of a new RAND study, European Contributions to Operation Allied Force: Implications for Transatlantic Cooperation . The research team, led by John E. Peters, found that, despite the success of the campaign, the experience of Operation Allied Force reemphasized the growing gap in military capabilities between the United States and Europe. The campaign displayed the difficulty of establishing and maintaining consensus in coalition warfare in which intra-Alliance political consultations are essential to produce any military action. It also highlighted differences in the perspectives of the United States and the European countries regarding such issues as the appropriate use of force and the legal basis for coalition operations.

The RAND study concluded that the United States should expect to continue to play the major role in future coalition operations. However, the Europeans should anticipate continuing pressure from the United States to improve their defense capabilities in the near term, particularly in the areas of deployability and sustainability. NATO's training exercises provide an opportunity for Alliance members and potential members to practice the skills needed for coalition warfare, including the consultations and deliberations required for consensus.

Lessons of Operation Allied Force

Operation Allied Force was officially supported by all 19 members of NATO. Thirteen countries contributed military aircraft to the operation, with France making the greatest contributions among the European countries in terms of deployed aircraft assets. According to the researchers, several key lessons emerged from NATO's 78-day operation in Kosovo:

Although Alliance and U.S. media news releases during the operation recognized the contributions of all participating air forces, the United States was responsible for a disproportionately large share of the effort. The Europeans certainly made some important contributions to combat operations. Germany and Italy played an important role in the campaign to suppress enemy air defenses, while the British and French joined the United States in delivering precision-guided munitions. However, the allies generally lacked the level of precision and all-weather capabilities that would allow them to carry out their missions by day and night while ensuring minimum civilian damage. The United States provided 700 of the 1055 aircraft deployed in the allied effort and flew by far the greatest number of sorties. The Europeans also lacked capabilities to deploy personnel and equipment to the field of operations and to sustain them as long as necessary. The United States provided more than 90 percent of aerial refueling aircraft, the bulk of airlift capabilities, and all tactical jamming capabilities.

Intra-Alliance politics made Operation Allied Force possible but also resulted in political and operational constraints that imposed limitations on warfare. The conditions of coalition warfare produced a relatively slow, deliberate air campaign, in contrast to the U.S. preference for high-tempo, continuous operations and overwhelming levels of force. The slower style of campaign was necessary to accommodate the consultative and deliberative functions of the coalition and to secure domestic and international popular support for the operation. Public support depended in large part on assurances that the risk of civilian casualties and damage was low. To minimize this risk, the Alliance limited the size, pace, targets, and amount of force used in the campaign.

Despite years of multinational, cooperative planning within the Alliance, the allies found it difficult to agree on a common approach. The consensus for action was fragile in the absence of an immediate threat to allied territory or traditional interests. Disputes within the Alliance centered on three issues: whether a "gradualist" approach to the air war would succeed, whether the United States had the right to keep some sensitive information in U.S.-only channels, and whether ground forces should be introduced. The last issue proved to be particularly contentious, even though none of the NATO members were eager to deploy ground forces. Ultimately, the discussion surrounding this issue may have helped sustain the consensus to continue the air campaign by reinforcing a shared belief that introducing ground forces would involve even more difficult and unpleasant issues.

Operation Allied Force highlighted some key differences in the perspectives of the United States and the European countries. The U.S. decision to maintain some information in U.S.-only channels occurred out of concern over the increased potential for information leaks in coalition operations. But many European countries resented the United States for what they considered to be overbearing control that excluded them from many decisions and minimized their involvement in others. In addition, many of the European allies were deeply uncomfortable with the legal basis of Operation Allied Force, which was carried out without the authorization of the United Nations or the Organization for Security and Cooperation in Europe (OSCE). In contrast, the United States argued that the NATO Treaty provided adequate justification for the Alliance to act wherever its interests were threatened.

The United States, NATO, and the European Countries Can Take Steps to Prepare for Future Coalition Operations

In light of the experience of Operation Allied Force, Alliance members must resolve several important issues to prepare for future coalition operations. The RAND report discusses key steps that can be taken by the United States and the European countries individually, as well as by the Alliance as a whole, to improve their capabilities for future coalitions.

The United States. The United States and especially the U.S. Air Force should expect to continue playing the role of allied force integrator in future coalition operations. Because of its military dominance, the United States has considerable leverage in designing military operations. During future campaigns, the United States may find it preferable to forge a consensus for more-vigorous action--even at the cost of some allies' participation. In the meantime, the United States can encourage allies to improve their military capabilities, particularly in the areas of deployability and sustainability. The United States should advocate that allied air forces emphasize multipurpose capabilities so that they can effectively participate in the full spectrum of operations--whether the coalition is producing overwhelming force or flying a handful of sorties a week. The United States should also support the development and use of NATO training exercises and scenarios that require participants to practice the consultations and deliberative actions needed for coalition operations.

NATO. Individually and collectively, the Alliance has much to grapple with from Operation Allied Force. The researchers identified six major issues demanding immediate attention:

  • Command structures. The Alliance should ensure that command structures are optimized for coalition operations, providing, at a minimum, a basic framework for headquarters and their subordinate units, complete with appropriate communications architectures.
  • Defense Capabilities Initiative (DCI). NATO officially launched the Defense Capabilities Initiative in 1999 as a means of improving the interoperability, deployability, and sustainability of NATO forces. The DCI has become a regular part of the annual NATO planning process during which member nations report the steps they are taking to improve their military forces. Since major additional defense spending among most of the allies is highly unlikely, the force planning process must adopt ways to prioritize those objectives the Alliance really wants its members to accomplish, such as deployability and sustainability.
  • Alliance-based assets. NATO should consider expanding the number of Alliance-based assets to include capabilities for intelligence, surveillance, and reconnaissance and electronic warfare.
  • System for operational decisions. A more responsive system is needed to allow NATO to request forces and assets from its members and to make operational decisions such as targeting.
  • Doctrine and military practices. The Alliance should investigate new ways to forge agreements on doctrine and military practices in a way that will approximate a common operational approach.
  • Consultation process. NATO must perfect and institutionalize a process of consultation and deliberation among its members.

The European countries. Individually, the European countries--including non-NATO states--face several challenges in their attempts to make progress toward capable, deployable, and sustainable forces within constrained budgets. Improvements may require trade-offs. Some countries may opt to reduce force size in order to finance modernization or to divert funding to certain key capabilities while allowing shortcomings in less-critical areas. Particularly important will be investments in complete, coherent, air-ground force packages.

One complexity in the development of European militaries concerns the role of the European Union (EU), whose membership overlaps with but does not duplicate the NATO roster. The EU is currently working to create a military capability to complement its economic and political capabilities. The EU is in the process of developing the institutions that will constitute the European Security and Defense Identity (ESDI), which will establish an independent European security and defense policy. At this time, the critical unanswered question about ESDI is its future relationship with NATO. The EU must ensure that the ESDI continues to develop in a way that complements and does not compete with NATO. The ESDI could potentially benefit NATO by promoting interoperability, deployability, and sustainability across the EU, thereby expanding the pool of potential coalition partners.

Implications for Future Coalitions

Drawing upon the lessons of Operation Allied Force, the authors made the following recommendations to guide planning for future coalition operations:

  • Because future coalitions may contain widely different capabilities, it will be necessary to design plans in such a way to allow all units to contribute. In most cases, the coalition leadership will have to be innovative to find effective roles for all participants.
  • It is possible that future coalitions may face circumstances in which some Alliance members participate in the humanitarian and peacekeeping phases of an operation, but not in combat should that occur. In some cases, members may not support the operation at all while non-NATO countries and even non-European countries choose to participate. Future coalitions must be prepared for such challenges to ensure that those states that do opt out do not restrict the range of options available to those states committed to combat.
  • Future coalitions may take place under conditions in which military operations are subordinate to political and diplomatic efforts that place limits on the scope of military action. In such circumstances, coalitions will have to be very creative to find ways to deliver appropriate and effective levels of military leverage that support political-diplomatic initiatives within the prescribed limitations.
  • A potentially serious consequence of coalition operations is that they may leave the enemy in power and in a position requiring further international supervision, such as the designation of no-fly zones. In each situation, future coalitions must determine the best course of action by weighing carefully the relative consequences of leaving an adversary intact or forcing him from power.
  • More systematic efforts must be made to collect and disseminate lessons learned from coalition operations and respond to them. The United States currently has some systems in place that can serve as models.
  • Multinational exercises are extremely important for ensuring interoperability with potential coalition partners and for working out command issues. NATO should improve its capability for exercises so that it can routinely integrate coalition-building and maintenance activities with military actions.

Research conducted by

This research brief describes work done for RAND's Project AIR FORCE.


