TRENTON, N.J. -- Nicholas deB. Katzenbach, who held influential posts in the Kennedy and Johnson administrations and played a prominent, televised role in federal desegregation efforts in the South, has died. He was 90.
Martin Mbugua, a spokesman for Princeton University, said Mr. Katzenbach died Tuesday night at his home in Skillman. He did not give a cause.
"Throughout his long and singular career in the nation's service, Nicholas Katzenbach combined realism, loyalty, and supreme equability with a bedrock devotion to principle, especially on civil rights, said Princeton University History Professor Sean Wilentz, a longtime friend of Mr. Katzenbach.
Mr. Katzenbach became deputy attorney general in 1963 and, after President John F. Kennedy's assassination, eventually served as attorney general and undersecretary of state under President Lyndon B. Johnson.
He helped work on the 1964 Civil Rights Act signed into law by Johnson, after having been the Kennedy administration's point man when James Meredith became the first black to enroll at the University of Mississippi in 1962.
The following year, Mr. Katzenbach was the federal official on hand when segregationist Alabama Gov. George C. Wallace made his infamous "stand in the schoolhouse door" -- symbolically attempting to block two black students, Vivian Malone and James Hood, from entering the University of Alabama.
Looking businesslike in a suit and tie, his bald head sweating under the Alabama sun, Mr. Katzenbach walked up to the school's entrance and handed Wallace, who stood in the shade, a presidential proclamation saying he must obey the law. The nation watched on television, including a nervous Robert F. Kennedy, then attorney general, in Washington.
In February 1965, Johnson picked Mr. Katzenbach as his attorney general, but he held the post for less than two years, feuding with FBI Director J. Edgar Hoover and others before stepping down in October 1966.
A short time later, he was named an undersecretary of state, a post he held for the remainder of the Johnson administration and which led to an unhappy entanglement with the Vietnam War.
In testimony before the Senate's Foreign Relations Committee in 1967, Mr. Katzenbach made a controversial defense of the war's legality, citing the 1964 Gulf of Tonkin resolution, which allowed the United States to repel attacks and prevent further aggression.
Mr. Katzenbach also became caught up in the nasty battle between his former boss, Robert Kennedy, and Johnson. In his 2008 memoir "Some of It Was Fun," Mr. Katzenbach wrote of a White House meeting he helped arrange and watching the two argue about Vietnam. Kennedy, who had become a senator from New York, had visited Vietnam and suggested a negotiated settlement was possible. Johnson accused him of weakening the United States.
"You have blood on your hands!" Mr. Katzenbach remembered the president shouting. Kennedy, "pale with repressed anger," left the room.
In 1969, after the Johnson administration ended, Mr. Katzenbach became IBM's general counsel. He also served on prison reform panels.