The Johnson Administration
Following Kennedy's assassination, the Johnson administration continued its military-based approach to winning the war. Mike Mansfield maintained public support for President Johnson and his administration, but he continued to oppose the war both publicly and through confidential memos.
After the assassination of President Diem in November 1963, President Johnson expanded U.S. military presence in Vietnam. Although a member of the President’s party, Mansfield stood firmly against military action. He was often the only one of the President’s advisors to express opposition to the escalation in Vietnam. Mansfield said, “It is only fair I give you my honest opinions…because to do otherwise would be a disservice to you and to the Nation.”
Years later, Mansfield shared with his biographer Don Oberdorfer an exchange he and Johnson had about Mansfield's lack of support for the war. "I started out, but he [President Johnson] turned around and said, 'I approve your honesty, but I only wish I had a majority leader who was more supportive.' I didn't say anything. He went his way. I went mine." (Intervew with Mike Mansfield, October 20, 1999, OH 391-001)