When Congress returns from its August recess, it will find a Congressional Budget Office (CBO) report in its in-box that estimates the cost for a boost-phase missile defense system to counter long-range ballistic missiles at between $16 billion and $78 billion.[1] The boost phase is the earliest portion of a ballistic missile's flight, when the missile's booster rocket is still burning. Members of Congress would do well to read the report because it will give them a sense of the technological tradeoffs involved in developing and deploying boost-phase interceptors. Opponents of missile defense in Congress, however, are sure to advocate terminating boost-phase programs based on CBO's cost estimate. Since these programs are all in the development phase, it is impossible to determine their advantages or their precise costs. A congressional decision to terminate boost-phase missile defense interceptor programs on this basis would therefore be premature and exceedingly unwise.

The Bush Administration's missile defense concept is based on a layered defense that would counter ballistic missiles in the boost, midcourse, and terminal stages of flight. Boost-phase programs, however, are lagging behind the mid-course and terminal programs at this time because of a 1993 decision by the Clinton Administration to terminate or downgrade these programs for policy reasons.[2] A decision to field boost-phase missile defenses will not be made this year or next, as these programs are still in the development stage. Were Congress to terminate these development programs again, that decision would be tantamount to rejecting the Bush Administration's missile defense concept before the technology has had a chance to demonstrate its utility.

Congress would do better to accelerate the development of boost-phase technologies, which will incur only a fraction of CBO's estimated costs, and leave the decision of which systems to field to a later date. This course will allow boost-phase technologies to catch up to the midcourse and terminal technologies and help Congress make a better-informed decision of which combination of systems to put into the field. On the same basis, Congress should seek to accelerate development of space-based technologies within the boost-phase program. Currently, the Missile Defense Agency's (MDA) proposed boost-phase development effort is skewed toward surface-based options.

Congress should keep the following specifics in mind about CBO's report on the cost of boost-phase missile defenses when it returns in September:

• The cost estimates for developing, fielding, and operating boost-phase missile defense systems depend on the estimator's assumptions. CBO is clear about the importance of these assumptions in its report. Varying assumptions explain why its estimates vary from $16 billion at the low end to $78 billion at the high end. These assumptions cover such things as the nature of the threat (both in types of missiles and numbers), the type of defense (surface-based or space-based), and the coverage of the defense (preferential or comprehensive), among others. As an example of differing assumptions leading to differing results, the Heritage Foundation's Commission on Missile Defense, in 1999, illustrated an approach to begin fielding a constellation of space-based interceptors for about $5 billion.[3] Concluding which assumptions to use is best made in the course of an intensified development effort.
   
• CBO's cost estimate includes 20-year life cycle costs. CBO's estimates, therefore, cover not only the cost developing and testing these systems, but also the costs of acquisition and operation. It is not necessary, or even advisable, for Congress to make a decision at this point about the specific type and number of boost-phase interceptors to put in the field. Rather, it should focus on creating a balanced development and testing program. The fact is that development and testing will cost less than half of CBO's projected overall costs. Congress should firmly reject the argument that the development and testing costs are by themselves unaffordable.
   
• CBO's cost estimates should be put into perspective. Because its cost estimates cover a 20-year period, CBO's report is likely to induce "sticker shock" in Congress. Congress should keep in mind that even CBO's upper estimate of $78 billion means spending less than $4 billion annually, on average. The overall missile defense program will cost roughly $10 billion in FY 2005. Further, this $4 billion is less than 1 percent of the overall projected defense budget for next year.
   
• Boost-phase defenses will likely be the most effective way to counter missiles carrying multiple warheads and decoys. Midcourse missile defenses attempt to destroy incoming missile warheads after their boosters have released them, along with any decoys the missile may carry. This requires deploying either a larger number of midcourse interceptors to intercept the multiple targets present, the ability to discriminate between real warheads and decoys, or both. While a midcourse element in a layered defense concept is appropriate, a boost-phase defense will destroy the missile before it releases individual warheads and decoys. This is why a boost-phase system is also a highly desirable piece of a layered defense.
   
• It is fair to infer from CBO's analysis that a constellation of high-velocity space-based interceptors will likely be the most effective of the boost-phase defense options. While a final conclusion in favor of high-velocity space-based interceptors must await further development, the relatively higher coverage rates and lower launch costs associated with these systems could make them the most competitive option. This is based on CBO's comparison of boost-phase defense options in terms of effectiveness and cost. The problem today is that MDA's priorities for developing boost-phase defenses, both in terms of timing and investment, are skewed in favor of surface-based concepts. This is particularly the case in its Kinetic Energy Interceptor (KEI) program. CBO's analysis should lead Congress to encourage MDA to balance its development efforts for boost-phase interceptors. This could be achieved by reconfiguring the KEI program to focus more keenly on lighter and faster kill vehicles that are more readily adaptable to basing in space.

Conclusion

As a direct result of the federal government's 30-year hiatus on fielding a defense against missile attack-a hiatus that fortunately will likely come to an end this fall-the U.S. missile defense program is lagging behind the threat. It is imperative that the overall missile defense program catch up to the threat and subsequently jump ahead of it. Boost-phase defense options will likely prove critical to achieving these goals. As a result, it would be foolish for Congress to terminate boost-phase defense programs, which are still in the phase of early development, on the basis of cost estimates that include their procurement and operation.

Baker Spring is F. M. Kirby Research Fellow in National Security Policy in the Kathryn and Shelby Cullom Davis Institute for International Studies at The Heritage Foundation.