The decision whether to proceed with Zeus eventually fell to President John F. Kennedy, who became fascinated by the debate about the system. In 1963, the United States Secretary of Defense, Robert McNamara, convinced Kennedy to cancel Zeus. McNamara directed its funding towards studies of new ABM concepts being considered by ARPA, selecting the Nike-X concept which addressed Zeus' various problems by using an extremely high-speed missile, Sprint, along with greatly improved radars and computer systems. The Zeus test site built at Kwajalein was briefly used as an anti-satellite weapon.
