Sea‐based missile defense is being advocated as an alternative to the Clinton administration’s limited land‐based national missile defense (NMD), which is in the early stages of testing. Proponents of sea‐based NMD (which is only a concept, not a program) argue that such a system can be deployed more quickly and will be less expensive than the Clinton administration’s land‐based system. Some argue that the Navy Theater Wide (NTW) system–which is being designed to provide midcourse intercept capability against slower, shorter‐range theater ballistic missiles–can be upgraded to attack long‐range intercontinental ballistic missiles (ICBMs) in their boost phase (when under powered flight at the beginning of their trajectories). Interestingly enough, advocates of sea‐based NMD include not only traditional supporters of missile defense but also people who were previously opposed to missile defense.
The claims made about sea‐based NMD and boost‐phase intercept capability should be viewed skeptically. The current NTW system does not have boost‐phase capability against ICBMs. The NTW interceptor cannot be easily and cheaply modified to provide such capability. In fact, a new interceptor would have to be designed and built, and a faster, larger interceptor with boost‐phase capability might not be compatible with the vertical launchers on Aegis ships. Moreover, the technological problems associated with sea‐based NMD are compounded by operational issues.
Finally, sea‐based NMD is really not a “national” missile defense system; it is the first step to a much larger and more expensive global missile defense system. Thus, the claims that sea‐based NMD is inexpensive do not ring true. Even if initial costs of sea‐based NMD are relatively low (which is a doubtful proposition), the follow‐on costs to deploy space‐based defenses will be significantly greater–in all likelihood by an order of magnitude or more–and certainly much greater than the cost of a limited land‐based system.