National Cruise Missile Defense: Issues and Alternatives
CBO examined the threat that adversaries equipped with land-attack cruise missiles might pose to the U.S. homeland and estimated the costs of several defensive systems that could be fielded to protect the United States from such attacks.
Since the 1980s, the United States has invested considerable resources to develop and field ballistic missile defenses to protect the U.S. homeland from attack by long-range ballistic missiles. In recent years, concerns have arisen that another type of weapon—land-attack cruise missiles (LACMs)—may also pose a threat to the U.S. homeland. Unfortunately, the systems that the U.S. military has deployed to protect the United States from ballistic missile warheads that fly high above the atmosphere are ill-suited to counter LACMs, which fly close to Earth’s surface.
This Congressional Budget Office report examines the potential for LACM attacks against the United States and the types of systems that might be fielded to provide a cruise missile defense with nationwide coverage. Such coverage would be analogous to that provided by national ballistic missile defenses.
CBO’s analysis yielded the following findings:
Cruise missiles could be used to attack the United States. Adversaries attempting such attacks could range from nonstate groups (including terrorists) that might be able to acquire a small number of missiles to “peer powers” (nations with large, advanced militaries) capable of launching much more sizable attacks.
Cruise missiles could be defeated with available technology, but a wide-area defense of the contiguous United States would be costly. Modified versions of systems that the military uses today could be purchased for homeland cruise missile defense. CBO estimates that the lowest-cost “architectures” it examined—integrated systems that comprise airborne or space-based radars, surface-to-air missiles, and fighter aircraft—would cost roughly $75 billion to $180 billion to acquire and operate for 20 years. Fielding additional regional or local defenses to protect Alaska, Hawaii, and U.S. territories would add to the cost.
Operational factors could hamper defenses. Because many civilian aircraft fly in U.S. airspace, targets would have to be positively identified as threats before defenses could engage them. However, very little time is available for defenses to act against LACMs, so any delay in achieving positive identification would significantly challenge the effectiveness of defenses, and even advanced battle management systems might be hard-pressed to respond in time. Also, adversaries could launch many LACMs to overwhelm defenses in a specific location.
Adversaries would have attractive alternatives to using LACMs. Because, in many circumstances, adversaries could attack the United States with systems that would be easier to successfully employ, less expensive, and potentially more damaging than LACMs—from truck bombs detonated by terrorists to ballistic missiles launched by Russia, China, and possibly North Korea—decisionmakers would need to consider whether the cost of a wide-area cruise missile defense was proportionate to the overall risk posed by LACMs.