President Bill Clinton and other opponents of national missile defenses charge it will cost too much to defend Americans against missile attack. 1 As evidence Clinton points to a May 15 estimate by the Congressional Budget Office (CBO) that a missile defense system required by the Defend America Act of 1996 would cost as much as $60 billion.2 Both the President and the CBO are wrong. Defending America from nuclear attack will not cost as much as the CBO thinks. The U.S. could deploy a missile defense system for as little as $8 billion. The CBO estimate is wrong because it is based on a flawed assumption that a ground-based sys- tem is the best option for ballistic missile defense (BMD). It is not. A sea-based option would not only be more effective, it would cost much less. Besides, the CBO report has been mischaracterized by critics of missile defense. All the critics say is that such a defense will cost $60 billion. What these critics ignore is that in the CBO estimate the initial de