Expert Commentary

U.S. military air strikes and air power: Research review and lessons from recent history

2014 roundup of research papers on American air strikes as a tactical and strategic action in countering insurgency, with an emphasis on their subsequent outcomes.

USS Philippine Sea, September 2014 (US Navy)
USS Philippine Sea, September 2014 (US Navy)

Information about U.S. air strikes being conducted in Syria against the Islamic State (ISIS) and other groups has so far largely been filtered through the Pentagon and the White House, as the ability to independently assess claims about their effectiveness is prevented by the dangerous on-the-ground environment. Much about the campaign’s true character remains unknown.

Given this, it is worth remembering that, although in some past conflicts air strikes have proven an effective tactic, in others — such as the launching of cruise missiles into Sudan and Afghanistan after the 1998 embassy bombings — air power has proven wholly ineffective according to expert accounts and after-action reviews. Even in regard to the Kosovo conflict, often seen as a relative success, researchers have drawn mixed conclusions about the role of air power. Air power during the early stages of the Iraq War, begun in 2003, seemed effective at a tactical level, before the insurgency later rapidly grew; likewise, NATO air strikes in Libya appeared to have been successful in 2011, but years later the true strategic results of that action still seem uncertain. Even deeper history remains relevant. New, data-driven research from scholars at Yale and Cornell on bombing during the Vietnam War suggests that strikes in civilian areas “systematically shifted control in favor of the Viet Cong insurgents.”

It remains an empirical question, then, how effective the strikes will ultimately be in curbing the activities of ISIS — and one that likely cannot be answered in a 24-hour news cycle, or even days or weeks. Just a year ago, when air strikes were being contemplated against the Assad regime in Syria, many analysts were warning that any intervention could lead to a long-run escalation by the groups fighting. Counterinsurgency experts have long pointed out that short-term gains through air strikes, such as the killing of leaders and the destruction of equipment, weapons and safehouses, can be offset by negative ripples through local populations, who may be pushed further into collaboration with insurgents. Impressive aerial images of destroyed vehicles and buildings, experts say, can mask more important changes in attitudes among local populations. Case studies illustrate just how this happens: Noted researcher and military thinker David J. Kilkullen has highlighted the problem of the “accidental guerrilla syndrome,” whereby the use of large-scale kinetic force by outside militaries can drive otherwise neutral locals to fight against them. Further, systematic research in places such as Afghanistan is revealing how populations are affected by a sense of victimization by outside forces.

This dynamic has been at the heart of a longstanding debate over the so-called “hearts and minds” question. It remains a key question, for example, with regard to the use of drones, or unmanned aerial vehicles (UAVs), in Pakistan, where experts continue to debate whether the program has produced positive results from a strategic point of view. Analysis of media coverage of the Obama administration’s drone warfare program shows that it took years before core questions about efficacy and legality (and morality, especially as it relates to civilian casualties) came to the surface and were discussed and analyzed in a more full and honest way.

Although news media accounts often focus on the latest wrinkle and anecdote from an official Pentagon account — and infrequently situate action in historical context — it is worth keeping in mind that there is a large research literature associated with air strikes, and that much of this can provide deeper, more contextual and, at times, more critical perspective. The following research papers furnish insights on the recent history of American air power, military intervention, and subsequent outcomes:


“Are Drone Strikes Effective in Afghanistan and Pakistan? On the Dynamics of Violence between the United States and the Taliban”
Jaeger, David; Siddique, Zahra. CUNY and Institute for the Study of Labor (Germany), December 2011.

Findings: The study uses the Worldwide Incidents Tracking System (WITS) database to understand the context of drone strikes in Afghanistan and Pakistan between January 2007 and December 2010 and to determine their impact on terrorist violence. The study’s findings include: In general “drone strikes matter, but only for Taliban violence in Pakistan. There is little or no [statistically significant] effect of drone strikes on Taliban violence across the border in Afghanistan.” The impact in Pakistan “varies from a positive vengeance effect in the first week following a drone strike to a negative deterrent/incapacitation effect in the second week following a drone strike, when we examine the incidence of terrorist attacks by the Taliban. The impact is negative in both the first and second week following a drone strike, when we examine the number of terrorist attacks by the Taliban.” The authors conclude, “We find some vengeance effects of drone strikes on violence by the Haqqani faction [of the Taliban] but also deterrent/incapacitation effects of drone strikes on violence by both the Haqqani and Mehsud factions of the Taliban. We estimate the differential effects of successful and unsuccessful drone strikes (which kill and do not kill a militant leader) on Taliban violence in Afghanistan and in Pakistan. We find strong negative impacts of unsuccessful drone strikes on Taliban violence in Pakistan, showing the deterrent effects of drone strikes are quite strong while the incapacitation effects of drone strikes are weak or non-existent.”


“The Costs and Consequences of Drone Warfare”
Boyle, Michael J. International Affairs, Volume 89, Issue 1, January 2013. doi: 10.1111/1468-2346.12002.

Abstract: “One of the distinctive elements of President Barack Obama’s approach to counterterrorism has been his embrace of Unmanned Aerial Vehicles (UAVs), or drones, to target terrorist operatives abroad. The Obama administration has used drones in active theatres of war, such as Afghanistan, but it has also dramatically increased the number of drone attacks launched by the CIA in other countries, such as Pakistan, Yemen and Somalia. The conventional wisdom on drone warfare holds that these weapons are highly effective in killing terrorist operatives and disabling terrorist organizations, while killing fewer civilians than other means of attack. This article argues that much of the existing debate on drones operates with an attenuated notion of effectiveness that discounts the political and strategic dynamics—such as the corrosion of the perceptions of competence and legitimacy of governments where drone strikes take place, growing anti-Americanism and fresh recruitment of militant networks—that reveal the costs of drone warfare. Focusing particularly on drone use in Pakistan, Yemen and Somalia, the article suggests that the Obama administration’s counterterrorism policy operates at cross-purposes because it provides a steady flow of arms and financial resources to build up governments whose legitimacy it systematically undermines by conducting unilateral strikes on their territory. It concludes that the US embrace of drone technology is a losing proposition over the long term as it will usher in a new arms race and lay the foundations for an international system that is increasingly violent, destabilized and polarized between those who have drones and those who are victims of them.”


“Kosovo and the Great Airpower Debate”
Byman, Daniel L.; Waxman, Matthew C. International Security, Spring 2000, Vol. 24, No. 4.

Excerpt: “As frequently happens in the aftermath of U.S. air operations, participants at both poles of the air power debate claimed vindication from Kosovo. But the key lesson of the Kosovo crisis is that neither side of this debate is, or can be, correct. This conclusion will strike many readers as unsatisfying because it urges participants to take several steps backward and reassess the terms of the debate rather than move forward and resolve it based on new data. The methodological propositions advanced in this article, however, should guide analysis of any instrument of coercion, whether military, economic, or diplomatic. When weighing the balance of ground and air forces (as well as the type of air forces needed), policymakers must consider not only what they seek to accomplish through coercion, but also what they seek to prevent. As the Kosovo contest attests, air power’s and other instruments’ greatest accomplishments are often what they preclude an adversary from doing. The role air power can play, for example, in stopping an adversary from shattering a coalition or generating domestic opposition in the United States has value beyond the damage it inflicts.”


“Aerial Bombing and Counterinsurgency in the Vietnam War”
Kocher, Matthew Adam; Pepinsky, Thomas B.; Kalyvas, Stathis N. American Journal of Political Science, Volume 55, Issue 2, April 2011. doi: 10.1111/j.1540-5907.2010.00498.x.

Abstract:Aerial bombardment has been an important component of counterinsurgency practice since shortly after it became a viable military technology in the early twentieth century. Due to the nature of insurgency, bombing frequently occurs in and around settled areas, and consequently it tends to generate many civilian casualties. However, the effectiveness of bombing civilian areas as a military tactic remains disputed. Using data disaggregated to the level of the smallest population unit and measured at multiple points in time, this article examines the effect of aerial bombardment on the pattern of local control in the Vietnam War. A variety of estimation methods, including instrumental variables and genetic matching, show that bombing civilians systematically shifted control in favor of the Viet Cong insurgents.”


“Who Takes the Blame? The Strategic Effects of Collateral Damage”
Condra, Luke N.; Shapiro, Jacob N. American Journal of Political Science, Volume 56, Issue 1, January 2012. doi: 10.1111/j.1540-5907.2011.00542.x.

Abstract: “Can civilians caught in civil wars reward and punish armed actors for their behavior? If so, do armed actors reap strategic benefits from treating civilians well and pay for treating them poorly? Using precise geo-coded data on violence in Iraq from 2004 through 2009, we show that both sides are punished for the collateral damage they inflict. Coalition killings of civilians predict higher levels of insurgent violence and insurgent killings predict less violence in subsequent periods. This symmetric reaction is tempered by preexisting political preferences; the anti-insurgent reaction is not present in Sunni areas, where the insurgency was most popular, and the anti-Coalition reaction is not present in mixed areas. Our findings have strong policy implications, provide support for the argument that information civilians share with government forces and their allies is a key constraint on insurgent violence, and suggest theories of intrastate violence must account for civilian agency.”


“Terrain Tribes and Terrorists: Pakistan, 2006-2008”
Kilkullen, David J. From The Accidental Guerrilla, Chapter 4, Oxford University Press, 2009. Published as part of the Brookings Counterinsurgency and Pakistan Paper Series, No. 3.

Excerpt: “Based on the above, it is clear that the campaign in Pakistan, since well before 9/11 but even more so since then, is a relatively classic example of the accidental guerrilla syndrome. AQ and other extremists moved into an already disrupted social framework in the FATA during and after the Soviet-Afghan war, infecting an existing problem of poor governance and societal weakness. The contagion effect from their presence (most obviously the 9/ 11 attacks themselves) brought a western-prompted intervention by the Pakistan Army into the FATA. The use of heavy-handed, overly kinetic tactics by troops who were mainly lowland Punjabis, culturally foreign to the area where they were operating, contributed to a societal auto-immune rejection response. The tribes coalesced and rose up to drive out the intrusion, resulting in the perpetuation of destructive patterns of what Akbar Ahmed called “resistance and control” on the frontier, and undermining the established, if loose, local governance system. Pumping additional assistance to Pakistan, without a fundamental rethink of political strategy, is therefore likely to be highly counterproductive in the long run.”


Close Air Support and Civilian Casualties in Afghanistan”
Dadkhah, Lara M. Small Wars Journal, Dec. 30, 2008.

Excerpt: “American air power seems to have lost some of its mystique in the war in Afghanistan. American air dominance, including its ability to conduct air strikes in close air support of coalition troops, has been and continues to be critical to the Afghan war effort. Close air support, in particular, is allowing the United States and NATO to fight an energized insurgency with far fewer troops than it needs. Yet if one follows press reports from the Afghan theatre, what Eliot Cohen once characterized as an “unusually seductive form of military strength,” has become a source of consternation for the United States and a ready cudgel with which to beat America’s troubled prosecution of Operation Enduring Freedom (OEF). Tragic news stories of American air strikes gone wrong and their resultant civilian casualties trump more mundane analyses of the Afghan government’s failings or the (by now routine) atrocities committed by Afghan insurgents. American air power, it seems, has become a victim of its own misunderstood successes in the Persian Gulf War and Kosovo bombing campaign. Its famed precision makes any costly error unacceptable, inflames Afghan and international public opinion, and forces American defense officials and military leaders to observe endless rituals of public apology. The irreconcilable conflict between the immutably violent nature of war and the fiction of a ‘bloodless’ use of force has trapped the United States between the Scylla of military exigency and the Charybdis of public sentiment.”


“In the Crossfire or the Crosshairs? Norms, Civilian Casualties, and U.S. Conduct in Iraq”
Kahl, Colin H. International Security, Summer 2007, Vol. 32, No. 1.

Abstract: “The belief that U.S. forces regularly violate the norm of noncombatant immunity (i.e., the notion that civilians should not be targeted or disproportionately harmed during hostilities) has been widely held since the outset of the Iraq War. Yet the evidence suggests that the U.S. military has done a better job of respecting noncombatant immunity in Iraq than is commonly thought. It also suggests that compliance has improved over time as the military has adjusted its behavior in response to real and perceived violations of the norm. This behavior is best explained by the internalization of noncombatant immunity within the U.S. military’s organizational culture, especially since the Vietnam War. Contemporary U.S. military culture is characterized by an “annihilation-restraint paradox”: a commitment to the use of overwhelming but lawful force. The restraint portion of this paradox explains relatively high levels of U.S. adherence with the norm of noncombatant immunity in Iraq, while the tension between annihilation and restraint helps to account for instances of noncompliance and for why Iraqi civilian casualties from U.S. operations, although low by historical standards, have still probably been higher than was militarily necessary or inevitable.”


“The True Worth of Air Power”
Pape, Robert A. Foreign Affairs, March/April 2004.

Abstract: “The leading advocates of the precision revolution have it exactly backwards. Precision weaponry has done little to enhance the coercive strength of enemy decapitation or other new strategies, which often fail because of inadequate intelligence. After a decade and a half of trying — and failing — to solve this intelligence problem, it may be time to recognize that it will not be overcome any time soon. Until it is, the combined use of air power and ground forces — whose potency has been multiplied by precision weapons — remains the most effective way for the United States to win major wars.”


“Allies, Airpower and Modern Warfare: The Afghan Model in Afghanistan and Iraq”
Biddle, Stephen. International Security, Winter 2005/06, Volume 30, Issue 3.

Abstract: “The Afghan model of warfare uses indigenous allies to replace American conventional ground troops by exploiting U.S. air power and small numbers of American special operations forces. Some argue that this model is widely applicable, enabling a major restructuring of the U.S. military and considerable freedom for American military intervention. An assessment of such claims in light of recent combat experience in Afghanistan and Iraq, however, finds the model’s applicability to be more limited. Where U.S. allies have had skills and motivation comparable to their enemies’, the Afghan model has proven extremely lethal even without U.S. conventional ground forces. But where U.S. allies have lacked these skills, they have proven unable to exploit the potential of American air power. The model can thus be a powerful tool, but one with important preconditions for its use—and these preconditions limit its potential to transform U.S. force structure or defense policy.”


“Making Civilian Casualties Count: Approaches to Documenting the Human Cost of War”
Steflja, Izabela; Darden, Jessica Trisko. Human Rights Review, December 2013, Volume 14, Issue 4.

Abstract: “Our understanding of civilian casualties is not based solely on what is reported but also who reports these human rights abuses. Competing interests at the data collection stage have impeded the development of a more thorough understanding of civilian victimization during conflict. We find that current definitions of “casualty” neglect nonphysical forms of victimization and that group-based definitions of “civilian” can obscure the role of different individuals in conflict. We contend that the dominant definition of “civilian casualty” should be expanded to include the full array of harm inflicted on individuals, including psychological harm and what we refer to as multiple casualties of conflict. Expanding our definition of civilian casualties to include different degrees and kinds of wartime victimization would improve both documentation and analysis. We propose several areas for improvement in terms of the documentation of civilian casualties as well as potential solutions to the problems we identify.”


“What Use Overwhelming Air Superiority? A Tale of Two Campaigns”
Steiner, Barry H. Contemporary Security Policy, Volume 33, Issue 2, 2012. doi: 10.1080/13523260.2012.693797.

Abstract: “Longer wars between mismatched opponents often end with the militarily weaker side showing unexpected strengths. This article tests this tendency in two short wars in which overwhelming force superiority was applied in massive air attacks. Operation Enduring Freedom (the 2001 American campaign in Afghanistan) and Operation Cast Lead (the 2008–2009 Israeli campaign in Gaza) both began with air offensives that shifted to air-supported ground combat, but Enduring Freedom (a Type A operation) gave priority to aerial attack, while in Cast Lead (Type B) air operations primarily paved the way for ground combat. Neither campaign was fully decisive, suggesting that the residual capabilities of weaker combatants apply to short as well as protracted hostilities. The Type A attack was decisive against the Taliban, but not against al Qaeda. The more intensive Type B case, Cast Lead, did not lead to greater decisiveness than its counterpart, with Israel emphasizing force demonstration to enhance deterrence of attack, yet not seeking to destroy Hamas’s residual military capability. The problem of translating large military superiority into decisive war results is also evident recently in more common, stretched out, and restrained air power use supporting higher-priority ground combat, as in NATO’s 2011 intervention in Libya and the aerial drone campaign in Pakistan supporting NATO war making in Afghanistan.”


“Libya’s Lessons: The Air Campaign”
Barrie, Douglas. Survival: Global Politics and Strategy, Vol. 54, No. 6, December 2012-January 2013. doi: 10.1080/00396338.2012.749629.

Excerpt: “The renewed demonstration of the importance of ISR [intelligence, surveillance and reconnaissance platforms] may have helped prompt NATO to finally move ahead with its Alliance Ground Surveillance project, an Alliance aspiration for nearly two decades. This will include five Global Hawk UAVs and support and exploitation infrastructure. These alone, however, will not address fully the gap in NATO’s ability organically to provide adequate situational awareness at the strategic, theatre and tactical levels. To be sure, even with its myriad imperfections and problems, NATO was an effective mechanism for delivering the desired military capability. Such operations, however, where air power is used to support local boots on the ground, should not be the default model for future interventions. The use of air power must be, and must be seen to be, judicious to ensure broad public support, particularly in campaigns justified on humanitarian grounds.”


Keywords: Afghanistan, Iraq, Pakistan, war, Syria, Middle East, Africa

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