"Katzenbach finally interrupted and said he knew about the Constitution, but a man could be a damn fool and be constitutional."

From David Halberstam's "The Best and the Brightest" (p. 345), reporting what the Attorney General Nicholas Katzenbach said when Secretary of State Dean Rusk, not wanting to pressure LBJ about Vietnam, "gave Katzenbach a long dissertation on the constitutional prerogatives of the President."

Nicholas Katzenbach died yesterday. He was 90.

There was speculation that Mr. Katzenbach left as attorney general [in 1966] in part to make way for Ramsey Clark, an assistant attorney general. President Johnson, it was said, wanted to make a historic appointment to the Supreme Court, choosing Thurgood Marshall to become the first black justice. Appointing Mr. Clark would prod his father, Justice Tom C. Clark, to resign from the bench to avoid a conflict of interest with his son. Ramsey Clark was appointed, Justice Clark did resign and Justice Marshall did succeed him.

As the No. 2 official at State, Mr. Katzenbach defended the legality of United States involvement in Vietnam, appearing before the Senate Foreign Relations Committee in August 1967 to argue that the Tonkin Gulf resolution, passed by Congress in 1964, had given the president the authority to widen the war.

Opponents of the war had hoped that he would follow in [the footsteps of the man he replaced, George W. Ball,] and challenge the administration’s policies from within. Mr. Katzenbach took a quieter tack, setting up a secret working group — “the Non-group,” he called it — to pursue ways to end the war. Mr. Katzenbach later said the group had added shades of gray to policy discussions and had contributed to bombing halts.

Another passage from "The Best and the Brightest" (pp. 420-421):

For Lyndon Johnson, the Tonkin Gulf Resolution was a victory, but like so many things he was to do in the coming year, it produced short-range gains with far more serious long-range problems. (However, ironically, the lack of legal authority for the war continued to bother not just the critics of the war but the President as well, and in 1965, as the escalation mounted, he turned to Nicholas Katzenbach, the Attorney General, and asked, “Don’t I need more authority for what I’m doing?” Katzenbach assured him that he did not, that on a legal basis he had all the authority he needed with the Tonkin Resolution. But Johnson was still bothered by the idea, and he raised the same point with his congressional liaison people and his friends on the Hill, and they told him not to go for more legal justification, that he would get hit from two sides: by the people who opposed him on the war, and by those who supported him but thought they had given him enough authority already.)