http://www.gwu.edu/~nsarchiv/news/20001218/

20 previously secret U.S. government documents detailing the policy debate over anti-ballistic missile defenses in the 1960's and early 1970's bring perspective to the problems -- such as technical failures and criticisms from allies and enemies alike -- that plague current efforts to deploy national missile defense. The National Security Archive, George Washington University, December 18, 2000