Joint Force Quarterly

Lessons from the war in Kosovo

Lessons from the war in Kosovo

Benjamin S. Lambeth

Allied Force, the most intense and sustained military operation in Europe since World War II, represented the first extended use of force by NATO as well as the first major combat operation conducted for humanitarian objectives against a state committing atrocities within its own borders. At a cost of more than $3 billion, it was also expensive. Yet in part because of that investment, it was an unprecedented exercise in the discriminate use of force, essentially airpower, on a large scale. There were highly publicized civilian fatalities; yet despite 28,000 high-explosive munitions expended over 78 days, no more than 500 noncombatants died as a direct result, a far better performance in terms of civilian casualty avoidance than either Vietnam or Desert Storm.

But Allied Force was a less than exemplary exercise in U.S. and NATO strategy and an object lesson in the limitations of Alliance warfare. A balanced appraisal must accordingly account not only for its signal accomplishments, but its shortcomings in planning and execution, which nearly made it a disaster.

Allied strikes against dispersed and hidden forces were largely ineffective, in part because of the NATO decision at the outset to forgo even the threat of a ground invasion. Hence Serb atrocities against the Kosovar Albanians increased even as air operations intensified. Some observers claimed that the bombing actually caused what it sought to prevent. Yet it seems equally likely that Milosevic would have unleashed some form of Operation Horseshoe, the ethnic cleansing campaign, during the spring or summer of 1999 in any event. Had NATO not finally acted, upward of a million Kosovar refugees may have been stranded in Albania, Macedonia, and Montenegro with no hope of return.

Although Allied air strikes were unable to halt Milosevic’s campaign before it was essentially accomplished, they completely reversed its effects in the aftermath of the cease-fire. More than 600,000 of the nearly 800,000 ethnic Albanian refugees from Kosovo returned home within two weeks of the air war’s conclusion. By the end of July, barely a month later, only 50,000 displaced Kosovar Albanians still awaited repatriation. By any reasonable measure, Milosevic’s bowing to NATO amounted to his defeat, and his accession to the cease-fire left him worse off than had he accepted the Rambouillet conditions, under which Serbia was to keep 5,000 security forces in Kosovo. Thanks to the settlement reached before the cease-fire, however, there are now none. Moreover, on the eve of Allied Force, Milosevic insisted as a point of principle that no foreign troops would be allowed on Kosovar soil. Today, with some 42,000 soldiers from 39 countries performing daily peacekeeping functions, Kosovo is an international protectorate safeguarded by both the United Nations and NATO, rendering any Serb claim to sovereignty over the province a polite fiction.

Second, the Alliance showed that it could function under pressure even in the face of hesitancy by political leaders of member states. In seeing the operation to a successful conclusion, it did something it was neither created nor configured for. The proof of success was that cohesion held despite the combined pressures of fighting a war and actually going into Kosovo with no fixed exit date even while bringing in new members.

Finally, for all the criticism directed at less steadfast Allies for their rear-guard resistance and questionable loyalty during the air war, even the Greek government held firm to the end, despite 90 percent of its population supporting the Serbs through large-scale street demonstrations. True enough, there remain unknowns about Allied steadfastness in future confrontations along Europe’s eastern periphery. Yet NATO maintained the one quality essential to Allied Force–integrity as a fighting cooperative.

Grinding Away

Despite its accomplishments, enough discomfiting surprises emanated from Allied Force to suggest that air warfare professionals should give careful thought to what still needs to be done to realize its joint warfare potential instead of basking in airpower’s largely singlehanded success. Many of the surprises entailed tactical shortfalls. Examples abound: the targeting process was inefficient, command and control arrangements were complicated, and enemy integrated air defense system challenges indicated much unfinished work in planning suppression of air defense. In addition, elusive enemy ground forces belied the oft-cited claim that airpower has arrived at the threshold of being able to find, fix, track, target, and engage any object on the surface of the earth.

There were likewise failings in strategy and operations. First, despite its successful outcome, the bombing effort was a suboptimal application of airpower. The incremental plan NATO leaders chose risked squandering much of the capital that had built up in airpower’s account following its ringing success in Desert Storm. The comment made by General Wesley Clark, Supreme Allied Commander Europe (SACEUR), that coalition forces would “grind away” at Milosevic rather than hammer him hard, attested to the watered-down nature of the strikes. By meting out the raids with such hesitancy, leaders remained blind to the fact that airpower’s very strengths can become weaknesses if used in ways that undermine its credibility. The first month of underachievement likely convinced Milosevic that he could ride out the assault.

Indeed, the way the operation commenced violated two of the most enduring axioms of military practice: surprise and keeping the enemy unclear of one’s intentions. A strategy that preemptively ruled out a ground threat and envisaged only gradually escalating air strikes was a guarantee for trouble downstream, even though it was the only strategy that seemed politically workable.

In fairness to the U.S. and NATO officials most responsible for air operations planning, many of the differences between Allied Force and the more satisfying Desert Storm were beyond Allied control. Bad weather was the rule. Variegated and forested terrain hampered sensors. Serb surface to air missile operators were more proficient and tactically astute than the lraqis. Alliance complications were far greater than the largely inconsequential intracoalition differences during the Persian Gulf War. Finally, because the goal was to compel rather than destroy, it was difficult to measure daily progress without a feedback mechanism to indicate the effect of the bombing on coercing Milosevic.

That said, the central question has less to do with platform or systems performance than with basic strategy choices NATO leaders made and what they suggest about lessons forgotten from previous conflicts. Had Milosevic been content to hunker down and wait out the bombing, he could have challenged long-term Allied cohesion and staying power. By opting instead to accelerate ethnic cleansing, he not only united the West but also left NATO with no alternative but to dig in for the long haul, both to secure an outcome that would enable the repatriation of displaced Kosovars and to ensure its continued credibility as a military alliance.

Efforts during the first month were badly under-resourced because of the prevailing assumption among NATO leaders that the operation would last just two to four days. The consequences included erratic target nomination and review, too few combat aircraft for both night and day operations, pressure for simultaneous attacks not only on fixed infrastructure targets but on fielded Yugoslav armed forces, an inadequate airspace management plan, and no flexible targeting cell in the combined air operations center (CAOC) for meeting General Clark’s sudden demands for attacking fielded forces in the engagement zone. All these problems were a reflection not on NATO mechanisms for using airpower per se, but on strategy choices either made or forgone by political leaders.

Capabilities for detecting and engaging fleeting ground targets improved as the Kosovo Liberation Army (KLA) became more active. Nevertheless, persistent problems with the flexible targeting effort spotlighted deficiencies. The CAOC went into the operation without an on-hand cadre of experienced target planners accustomed to working together. Accordingly, leaders were forced to resort to a pick-up team during the first month of operations against Yugoslav forces. The fusion cell also frequently lacked ready access to all-source reconnaissance information.

The nature of the operation and the way it was conducted from the highest levels in Washington and Brussels placed unique stresses on the ability of Lieutenant General Michael Short, USAF, the combined forces air component commander (CFACC) to command and control air operations. For example, leaders had to contend with continuous shifts in political priorities and SACEUR guidance as well as myriad pressures occasioned by a random flow of assets to the theater, ranging from combat aircraft to staff augmentees in the CAOC. These problems emanated from a lack of consensus on both sides of the Atlantic as to the military goals at any given moment and what it would take to prevail. The de facto no friendly loss rule, stringent collateral damage constraints, and the absence of a ground threat to concentrate enemy troops into easier targets further limited the rational employment of in-theater assets and placed a premium on accurate information and measures that took a long time to plan and carry out. One realization driven home was the need for targeting cell planners to train together routinely before a contingency.

The greatest frustration of Allied Force was its slow start and creeping escalation. A close second entailed uniquely stringent rules of engagement that constrained combat sorties. Indeed, the dominance of political inhibitions was a unique feature. Because the air war was an essentially humanitarian operation, neither the United States nor the European Allies saw their security interests threatened by ongoing events in Yugoslavia. The perceived stakes were not high at the outset, so committing early to a ground offensive was out of the question. Moreover, both the anticipated length of the bombing and the menu of targets were bound to be matters of heated contention.

Dark Future

Although Allied Force did not exhibit the ideal use of airpower, it suggested that gradualism may be here to stay if U.S. leaders opt to fight more wars for amorphous interests with a disparate set of allies. Gradualism suggests that airmen will need discipline whenever politicians hamper the application of a doctrinally pure campaign strategy. War is ultimately about politics, and civilian control of the military is in the democratic tradition. While warfighters are duty-bound to argue the merits of their recommendations to civilian superiors, they also have a duty to make the most of the hands they are dealt in an imperfect world. Senior civilian leaders have an equal obligation to stack the deck so the military has the optimal hand to play and the fullest freedom to do its best. That means expending the energy and political capital needed to develop and enforce a strategy that maximizes the probability of military success. Most top civilian leaders on both sides of the Atlantic failed to do that in Allied Force.

On the plus side, the success of the war suggested that U.S. airpower may have become capable enough to underwrite a strategy of incremental escalation despite inherent inefficiencies. What made the gradualism of Allied Force more bearable was that the NATO advantages in stealth, precision standoff attack, and electronic warfare allowed the Alliance to fight a one-sided war with near impunity and achieve the desired result even if not in the ideal way.

With the air weapon now largely perfected for such established situations as halting massed armored assaults, it needs to be further refined for handling messier, less predictable, and more challenging combat situations–elusive or hidden enemy ground forces, restrictive rules of engagement, disagreeable weather, enemy use of human shields, lawyers in the targeting loop as a matter of practice, and diverse allies who have their own political agendas–all of which were features of the Kosovo crisis. Moreover, although NATO political leaders arguably set the bar too high with respect to collateral damage avoidance, it seems the Western democracies have passed the point where they can contemplate using airpower, or any force, in ways as unrestrained as World War II bombing. That implies that along with new precision-attack capability goes new responsibility, and air warfare professionals must now understand that they will be held accountable.

One can fairly suggest that both SACEUR and CFACC were equally prone throughout Allied Force to remain wedded to excessively parochial views of their preferred target priorities, based on implicit faith in the inherent correctness of service doctrine. Instead, they might more effectively have approached Milosevic as a unique rather than generic opponent, conducted a serious analysis of his particular vulnerabilities, and then tailored a campaign plan aimed at attacking those vulnerabilities directly, irrespective of canonical land or air warfare solutions for all seasons.

Finally, the probability that future coalition operations will be the rule rather than the exception suggests a need to work out ground rules before a campaign, so operators, once empowered, can implement the agreed plan with minimal political friction. As it was, Allied Force attested not only to the strategy legitimation that comes from the force of numbers a coalition provides, but also to the limitations of committee planning and least-common-denominator targeting.

The Ground Option

One of the most important operational and strategic realizations was that a ground component to joint campaign strategies may sometimes be essential to enable airpower to deliver to its fullest potential. General Richard Hawley, USAF, the former commander of Air Combat Command, was one of many senior airmen who admitted that the a priori decision by the Clinton administration and NATO political leaders not to employ ground forces undercut air operations: “When you don’t have that synergy, things take longer and they’re harder, and that’s what you’re seeing in this conflict.” (1)

Had Yugoslav forces faced an imminent ground invasion, or even a credible threat of one later, they would have been obliged to move troops and supplies over bridges that NATO aircraft could have dropped. They also would have been compelled to concentrate and maneuver in ways that made it easier to find and attack them.

Earlier, Samuel Berger, the National Security Adviser to the President, maintained that taking ground forces off the table had been right because anything else would have prompted an immediate public debate both in the United States and abroad which could have split the Alliance. Yet there was a huge difference between acknowledging that a land offensive could be perilous and categorically ruling one out before the fact. Considering a land offensive would have been demanding enough under the best of circumstances because of basing, airlift, and logistic problems; but denying the possibility of one was a colossal strategic mistake in that it gave Milosevic the freedom to act against the Kosovar Albanians and determine when the war would end. The anemic start of Allied Force because of the lack of an accompanying ground threat created opportunity costs that included failure to exploit the shock potential of airpower and to instill in Milosevic an early fear of more dire consequences to come. It encouraged enemy troops to disperse and hide while they had time, extended carte blanche to accelerate atrocities, and relinquished the initiative.

As for the oft-noted concern over an unbearable level of friendly casualties from ground action, there likely would have been no need to actually commit NATO troops to battle. The mere fact of a serious Desert Shield-like deployment of ground troops along the Albanian and Macedonian borders would have made the enemy more easily targetable by airpower. It might also have lessened or deterred ethnic cleansing. In both cases, moreover, it could have enabled a quicker end to the war.

Even had Milosevic remained unyielding to the point where an opposed ground-force entry became unavoidable, continued air preparation of the battlefield might have prevented the residual enemy strength from significantly challenging land forces. Impending weather improvements and further air dominance would have enabled more effective air performance against targets, especially had KLA forces maintained enough pressure on the Serbs to bunch up and move.

The problems created by ruling out a ground option suggest art important corrective to the argument over airpower versus boots on the ground. Although Allied Force reconfirmed that friendly ground forces need no longer be inexorably committed to combat early, it also reconfirmed that airpower often cannot perform to its potential without a credible ground component in the campaign strategy. Airpower alone was not well suited to defeating Yugoslav forces in the field. Once the returns were in, it was clear that few kills were accomplished against dispersed and hidden units. Moreover, airpower was unable to protect the Kosovar Albanians from Serb terror tactics, a problem exacerbated by the stringent rules of engagement aimed at minimizing collateral damage and avoiding any NATO loss of life. As General Merrill McPeak, the former Chief of Staff of the Air Force elaborated, “In a major blunder, the use of ground troops was ruled out from the beginning. I know of no airman–not a single one–who welcomed this development. Nobody said, ‘Hey, finally, our own private war. Just what we’ve always wanted!’ It certainly would have been smarter to retain all the options …. Signaling to Belgrade our extreme reluctance to fight on the ground made it much less likely that the bombing would succeed, exploring the limits of airpower as a military and diplomatic instrument.” (2)

Good Luck and Bad Weather

As for what should be learned from Allied Force, the head of the U.S. military contribution, Admiral James Ellis, made a good start in his after-action briefing to Pentagon and Allied officials, declaring that luck played the chief role. The commander of JTF Noble Anvil charged that NATO leaders “called this one absolutely wrong.” Their failure to anticipate what might occur once their initial strategy of hope did not succeed caused most of the untoward consequences, including the hasty activation of a joint task force, a race to find suitable targets, an absence of coherent campaign planning, and lost opportunities resulting from not adequately considering the unexpected. Ellis concluded that the imperatives of consensus politics made for an “incremental war” rather than “decisive operations,” that excessive concern over collateral damage created “sanctuaries and opportunities for the adversary-which were successfully exploited,” and that the lack of a credible ground threat “probably prolonged the air campaign.” (3) It was only because Milosevic made a blunder no less towering than ruling out a ground option that the war had a largely positive outcome.

The Kosovo experience further suggested needed changes in both investment strategy and campaign planning. The combination of marginal weather and the unprecedented stress placed on avoiding collateral damage made for numerous delays between March 24 and midMay, when entire air tasking orders had to be canceled and only cruise missiles and B-2s, with their through-the-weather capability, could be used. That spoke powerfully for broadening the ability of other aircraft to deliver accurate munitions irrespective of the weather, as well as for ensuring adequate stocks. The extended bad weather underscored the limitations of laser-guided bombs and confirmed the value of global positioning system-guided weapons.

The munitions generally performed as advertised. Results, however, confirmed the need for a larger inventory of precision-guided munitions (especially those capable of all-weather target attack), as well as greater accuracy and more standoff attack capability. At the same time, they indicated a continued operational utility for both unguided general-purpose bombs and cluster munitions for engaging soft military area targets deployed in the open. Other areas for improvement included interoperability across platforms, more multispectral sensors, higher-gain optical sensors for unmanned aerial vehicles, more data link interoperability, a wider range of bomb sizes, and weapons capable of conducting auto-bomb damage assessment. Still other force capability needs included better means for locating moving targets, better discrimination of real targets from decoys, and a way of engaging those targets with smart submunitions rather than costly precision-guided munitions and cruise missiles.

Viewed in hindsight, the most remarkable thing about Allied Force was not that R defeated Milosevic, but that airpower prevailed despite a risk-averse U.S. leadership and an Alliance often held together only with paralyzing drag. Although airpower can be surgically precise, it is in the final analysis a blunt instrument designed to break things and kill people in pursuit of clear and militarily achievable objectives. Indeed, air war professionals have insisted since the Vietnam War that if all one wishes to do is send a message, use Western Union.

To admit that gradualism of the Allied Force sort may be the wave of the future for U.S. involvement in coalition warfare is hardly to accept that it is thus justifiable from a military standpoint. Quite the contrary, the incrementalism of the air war for Kosovo involved a potential price beyond the loss of valuable aircraft, munitions, and other expendables for questionable gain right up to the end. It risked frittering away the hard-earned reputation for effectiveness that U.S. airpower had finally earned in Desert Storm after more than three years of unqualified misuse over North Vietnam a generation earlier.

U.S. airpower as it has evolved since the mid-1980s can do remarkable things when employed with determination in support of a campaign whose intent is not in doubt. Yet to conjure up the specter of air strikes, conducted by NATO or otherwise, for the appearance of doing something without initially weighing intended targets or consequences, risks getting bogged down in an operation with no plausible theory of success. After years of false promises by its most outspoken prophets, airpower has become a vital instrument of force employment in joint warfare. Even in the best of circumstances, however, airpower can never be more effective than the strategy it supports.


(1) Bradley Graham, “General Says U.S. Readiness Is Ailing,” The Washington Post, April 30, 1999.

(2) Merrill A. McPeak, “The Kosovo Result: The Facts Speak for Themselves,” Armed Forces Journal International (September 1999), p. 64.

(3) Elaine M. Grossman, “For U.S. Commander in Kosovo, Luck Played Role in Wartime Success,” Inside the Pentagon, vol. 15, no. 36 (September 9, 1999), p. 1.

Benjamin S. Lambeth is a senior staff member at RAND and the author of NATO’s Air War for Kosovo: A Strategic and Operational Assessment.

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