Clark Clifford interview Clifford, a longtime Democratic Party insider and advisor, replaced Robert McNamara as Secretary of Defense in 1968. In this brief interview, he explained why President Johnson stopped the escalation of the war after the Tet Offensive. Rostow interview A former MIT professor, Rostow served Presidents Kennedy and Johnson in many capacities throughout the decade of the sixties. He consistently advocated for a vigorous prosecution of the Vietnam War and discussed here why public support for his position declined after the Tet Offensive.