Actually 00000000, according to Bruce Blair's first-hand account. He has been one of the go-to authors on nuclear weapons control issues for many years. (Receiv

Actually 00000000, according to Bruce Blair's first-hand account. He has been one of the go-to authors on nuclear weapons control issues for many years. (Received a MacArthur Prize for it, in fact.) See http://www.cdi.org/blair/permissive-action-links.cfm http://www.cdi.org/blair/permissive-action-links.cfm.