Why Bombing Syria Isn't Likely to Work

Air power coercion succeeds only about a third of the time


B2 Bomber in air formation
Public Domain

"Air power is an unusually seductive form of military strength, in part because, like modern courtship, it appears to offer gratification without commitment," the political scientist Eliot Cohen wrote in 1994. President Barack Obama and the U.S. Congress seem poised to succumb to the seductions of air power as they try to fashion some way to stop Syrian dictator Bashar al-Assad from using chemical weapons against his opponents. Will our politicians be gratified? Can they avoid commitment? The scholarly literature suggests not.

But first, let's briefly trace how the Obama administration backed itself into this unlovely corner. Two years ago, President Obama declared that Assad must "step aside." The tyrant remains in power, and the recent momentum of the Syrian civil war seems to be running in his favor. Last year, the president asserted that if Assad used chemical weapons he would cross a "red line" that would change Obama's "calculus" about what to do about Syria.

Obama told an audience in Sweden on Wednesday that he did not set a red line but the international community did, since countries representing 98 percent of the world's population have ratified the Chemical Weapons Convention. It bears noting that Syria is one of seven countries that has not.

So will raining missiles down on Damascus stop Assad from gassing his people in the future? Quantitative research by Michael Horowitz of the Center for Strategic and International Studies and Dan Reiter of Emory University suggests that threatening such aerial attacks works about a third of the time. In their 2001 article "When Does Aerial Bombing Work?" in the Journal of Conflict Resolution, the two define coercion as "a threat to inflict pain on a target if the target does not accede to a demand." The two identify and analyze all attempts to use air power to coerce countries between 1917 and 1999. "Of our 53 cases of air power coercion, 19 (36 percent) were successes and 34 (64 percent) were failures," they report.

Horowitz and Reiter define air power coercion a "success" when a target changes its behavior as demanded without being attacked. ("Successful threats are those that do not have to be carried out," as the economist Thomas Schelling wrote in his 1966 book Arms and Influence.) Clearly, the threat of U.S. air power has failed to dissuade Assad from poison gassing his people. The researchers also count air-power coercion as successful if a target yields shortly after being attacked. With regard to Syria, that kind of "success" is still up in the air, so to speak.

Air power coercion "fails" when a target refuses to comply and no attack follows the coercer's threat. Such a failure would occur if Congress refuses to authorize an attack on Syria and the president observes this constitutional constraint. Coercion also fails when would-be coercer abandons its follow-on attacks before the target accedes, or when the coercer must utterly destroy the target before it gives in. In other words, attempts to coerce solely using air power fail when a target calls the coercer's bluff, withstands limited bombing, or must be conquered.

The analysis found that air power coercion is most likely to succeed when its military assets are particularly vulnerable and when the coercer's demands do not amount to an ultimatum that the target country change its regime. In this case, Syria will have had up to three weeks to reduce its military vulnerability to aerial attack by scattering its forces and hardening targets. Thus the efficacy of a U.S. bombing and missile attack to degrade to Assad's military assets, including his chemical weapons stocks, has been significantly blunted. Furthermore, the White House's manifest goal of overthrowing the Assad regime will strengthen its resolve to resist U.S. demands. 

The president has also declared that whatever aerial attack the U.S. launches at Syria will be a "limited, proportional step." The current version of the congressional resolution authorizing an attack limits the effort to 90 days and forbids the introduction of troops on the ground. Assad will reasonably conclude that he can outlast the bombs and missiles because the U.S. is not ultimately serious about enforcing its demands.

Proponents of a bombing campaign could counter that the Libyan civil war is the more accurate template for assessing the probable efficacy of a U.S. attack on Syria. Clearly, air power supplied by NATO allies was crucial to overthrowing Libyan dictator Muammar Qaddafi. In that case, the United Nations Security Council authorized "all necessary measures…to protect civilians and civilian populated areas." The same resolution also explicitly excluded "a foreign occupation force of any form on any part of Libyan territory." In "Libya's Lessons: The Air Campaign," a paper published in the January 2013 issue of Survival, Douglas Barrie of the International Institute for Strategic Studies acknowledges the vital role that NATO air power played in Libya. NATO planes, missiles, and bombs gave the Libyan rebels the time to obtain weapons from abroad and develop rudimentary military capabilities.

President Obama agreed in June to ship some weapons to the Syrian rebels after the disclosure that the Assad regime had evidently used chemical weapons to kill civilians back in December 2012. Perhaps Syrian rebels armed by the U.S. and backed by American air power could make significant headway against Assad's military forces. However, the administration has not yet delivered any of the promised weapons, due to reasonable fears that the guns, grenades and rockets might end up in the hands of radical Islamist such as the Al Nusra Front.

Considering how badly the situation in Libya is deteriorating, the Obama administration has reason to worry about what would happen if the Syrian rebels do actually win. Even as Barrie argues that aerial coercion succeeded in Libya, he cautions, "Such operations, however, where air power is used to support local boots on the ground, should not be the default model for future interventions." Unfortunately, history teaches that those boots, once in power, are all too likely to stomp on the rights of fellow citizens. In any case, it is doubtful that a limited and proportional aerial attack will tip the Syrian civil war toward a rebel victory.

Threats have already failed to coerce, and the limited aerial attacks contemplated by President Obama are not apt to much change Assad's military calculations. History and the reckonings of political science argue that Congress and the president should shun the seductions of air power. They are not likely to be gratified, and they could all too easily be drawn into a commitment that they and the rest of us would soon rue.