An attack that sank a carrier with significant casualties, on the other hand, might well result in demands for vengeance, the specific circumstances of the attack notwithstanding. This could put U.S. policymakers in the awkward position of needing to escalate, without being able to use some of the most lethal military options in their toolkit.

Since the 1950s, the supercarrier has been the most visible representation of U.S. military power and maritime hegemony. Although supercarriers have participated in nearly every military conflict since the commissioning of USS Forrestal in 1955, no carrier has come under determined attack from a capable opponent. In part, this is because supercarriers are very difficult to attack, but the symbolic grandeur of the massive ships also plays a role; no one wants to know what the United States might do if one of its carriers came under attack.

(This first appeared several months ago.)

What would happen if a foe attacked a United States Navy (USN) aircraft carrier during a conflict? How would the United States react, and how would it respond?

Circumstances: 

Circumstances obviously matter for an attack on a U.S. aircraft carrier. An out-of-the-blue attack from a conventionally armed state actor would enjoy the highest levels of success, but would also have an impact on elite and public opinion in the United States that might drive calls for dire retribution. An attack as part of a crisis would seem less extraordinarily hostile, but would nevertheless incur demands for a severe response. Finally, an attack during active hostilities might well represent a significant escalation but would be least likely to elicit an enraged public response. Most devastating of all might be an attack by a non-state actor that resulted in significant casualties and/or the destruction of the carrier. This would undoubtedly inflame U.S. public opinion while leaving the United States without a clear path for response and retribution.

Escalatory Logic: 

As part of an ongoing military conflict, an attack against a USN carrier would not necessarily represent a legal challenge; aircraft carriers are weapons of war, after all, and they are just as vulnerable to attack as any other weapon. But as military theorists have pointed out for at least two centuries, states choose their levels of escalation very carefully. Most wars are limited wars, and in limited wars, generals, admirals, and politicians are aware of the political import of the targets they select. Consequently, some targets remain off-limits for states that want to keep a war limited, even if those targets make a material contribution to the conduct of the conflict.

The United States has enjoyed, for quite some time, a perception of untouchability around its most cherished, expensive, and effective military assets. Even with conventional naval and air forces, attacking a supercarrier is no mean task; the USSR tried to develop effective anti-carrier weapons and tactics for decades, a pursuit that China has now taken up. But aircraft carriers have an almost mythic symbolic importance, both in global opinion and in the self-conception of the U.S. Navy. No state has undertaken a determined attack against a USN carrier since World War II.

Authorizing an attack against a USN supercarrier would require a weighty political decision. Political and senior military authorities might prefer to simply damage a carrier, which would send America a message about vulnerability but that would not necessarily lead to the deaths of extensive numbers of U.S. personnel. However, it would be difficult for anyone to guarantee limitations on damage, as a "lucky shot" might destroy the carrier. Granting the authority to attack a carrier would necessarily run the risk of sinking the ship. The USS Nimitz carries almost 6000 American military personnel and represents a vast expenditure of American treasure. Attacking her, and thus endangering this blood and treasure, is a very risky prospect indeed. The sinking of a U.S. aircraft carrier might well result in casualties that would exceed the total losses of the Iraq War in no more than a few minutes. When capital ships sink, they sometimes take nearly every crew member with them; 1415 of a crew of 1418 went down with HMS Hood in 1941, for example.

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The targets of an attack against a carrier, in effect, would be U.S. military capabilities, public opinion, and elite opinion (defining elite as including military and civilian leadership). The political and military leadership of the foe would need to believe that attacking the carrier was militarily feasible, that it would further operational or strategic goals, and that the likely U.S. responses were manageable in military and political terms. On the operational and strategic levels, it's not difficult to imagine a context in which damaging, destroying, or deterring a carrier would enable operational military success. Simply clearing the skies of F/A-18s and F-35s tends to make life easier for fielded military forces. On the strategic side, an attack would convey a seriousness of commitment, while creating fear of vulnerability in America. Damaging or sinking a carrier would make the costs of war starkly clear to Americans, and might dissuade them from further conflict. Finally, any decision to escalate must take the potential U.S. response seriously and including either that America would not escalate in response or that any U.S. response could be effectively managed.

Impact: 

Much would depend on the effectiveness of the attack. Even an unsuccessful attempt at attacking a supercarrier (an intercepted submarine sortie or a volley of ballistic missiles that failed to reach the target, for example) would carry escalatory risks, although it would also indicate seriousness of purpose to U.S. policymakers.

The military impact of a successful strike against a carrier would be straightforward. A missile volley that either sank a carrier or led to a “mission-kill” by damaging the flight deck of a carrier into inoperability would deeply affect U.S. military operations, both by removing the carrier from the fight and from deterring America from deploying other carriers to the region. The USN can deploy only a limited number of carriers at any given time. In a crisis, the USN could shift carriers around and stand up additional ships, but knocking out a carrier effectively eliminates around 10 percent of American naval aviation strike power. The United States has other options (land-based air, cruise missiles, assault carriers), but in many scenarios damaging or sinking a carrier could have a dramatic impact on the military balance.

However, a “mission-kill” would not necessarily inflame U.S. public opinion, and might even create a sense of vulnerability among the American people. Perhaps more importantly, such an attack might give U.S. policymakers (who have historically been more casualty-averse than the U.S. public) pause over the costs and benefits of the intervention. An attack that sank a carrier with significant casualties, on the other hand, might well result in demands for vengeance, the specific circumstances of the attack notwithstanding. This could put U.S. policymakers in the awkward position of needing to escalate, without being able to use some of the most lethal military options in their toolkit.

But again, the attacker would run severe risks. Damaging or sinking a carrier could result in a much stronger U.S. commitment to the conflict, as well as a U.S. decision to escalate either vertically (by using additional weapon systems) or horizontally (by widening the geographic scope of the fight). Sinking a carrier would be a great way to turn a limited war into a major war, and there are very few countries that would seriously contemplate major war against the United States.

Final Salvo: 

It is not likely that any foe will decide to attack a USN supercarrier by accident. Launching an attack against a carrier represents a profound political-military decision to escalate the stakes of a conflict, and it is unlikely that a tactical commander (a sub skipper, for example) would be allowed to make such a decision on his or her own. If such an attack ever takes place during a crisis or a conflict, the policymakers on either side (not to mention the rest of the world) will need to take very deep breaths and think hard about what the next steps might be.

Robert Farley, a frequent contributor to TNI, is a Visiting Professor at the United States Army War College. The views expressed are those of the author and do not necessarily reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government.