Key point: Sinking a carrier will not be so easy.
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.
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 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.
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.