Joseph A. Califano Jr. was President Lyndon B. Johnson’s top White House assistant for domestic affairs and secretary of health, education and welfare under President Jimmy Carter. This op-ed is adapted from his memoir “Inside: A Public and Private Life.”

In June 1963 Cyrus Vance, then secretary of the Army , named me general counsel of the Army and gave me my first assignment: Represent the Defense Department in connection with the march on Washington planned for Aug. 28.

Seventy-four-year-old civil rights veteran A. Philip Randolph was organizing the march in support of public-school integration and passage of fair-employment practices and civil rights legislation. Randolph enlisted Bayard Rustin, Martin Luther King Jr., Walter Fauntroy, James Farmer and John Lewis to put it together. They hoped to bring 100,000 people to the capital.

Vance told me that he and Attorney General Robert Kennedy feared the march was fraught with potential for violence. John Douglas, an assistant attorney general, and I were to represent the federal government in meetings with the organizers. At our first meeting, it became clear that the situation was indeed perilous. Rustin, a Quaker and veteran civil rights leader, and Fauntroy, a 30-year-old clergyman, were a combustible mixture of total commitment and utter disorganization. They had given no consideration to logistics or protection for thousands of civil rights marchers assembled on the Mall.

At a meeting in his office on Aug. 16, 1963, the attorney general said he feared that an unruly demonstration could set back efforts to desegregate Southern schools. The president’s civil rights legislation was already in terminal trouble in Congress, he said, and the march — especially if violence erupted — would kill what little hope remained for action.

The D.C. police wanted to use dogs. The National Guard wanted to carry firearms. We quickly agreed that the D.C police would not be permitted to use dogs. Vance and I wanted the National Guard to have only billy clubs. We feared that someone in the all-white guard, which was not as well trained as regular Army troops, might fire a gun unnecessarily. Kennedy agreed.

We discussed dozens of logistical details: how to get trains in and out of Washington, where to park buses, whether to alert troops in the area, whether to pre-position the 82nd Airborne Division, what federal leave policy should be, whether to close all bars and liquor stores (we did), what water and medical facilities would be needed for a blistering hot day, and how to prepare for the worst.

No administrative leave was granted to federal employees. Already accused of promoting the march, President John F. Kennedy wanted to deny political opponents any opportunity to charge in the 1964 presidential campaign that the administration had swelled the number of marchers with federal workers.

The attorney general wanted as much religious participation as possible and pulled on the family’s Roman Catholic connections to produce priests in collars and nuns in habits.

It was critical to both Kennedys that the marchers be in and out of Washington on the same day. He worried that demonstrators staying overnight increased the risk of violence and clashes with angry whites opposed to the march. We insisted, therefore, that charter bus companies and trains transport marchers out of town that evening and that District police prohibit buses and cars from parking overnight. We quietly encouraged hotels to demand gouge prices, which they were happy to do; still largely segregated, they didn’t want their rooms filled with black people.

The attorney general did not want civil rights leaders to know that the administration was behind the push to get them out the same day. I was instructed to attribute the decision entirely to the Army’s concern about security (which was real enough). The greatest resistance to this tactic came from Patrick O’Boyle, the first Roman Catholic archbishop of Washington. He was placing cots for the marchers in church basements and Catholic school gymnasiums and calling on other churches to do the same. When I asked O’Boyle to stop, he was appalled: “What about old people? People who get sick? Who might collapse from exhaustion or have heart attacks if they have to go back that evening?” Knowing that I was Catholic, he deplored my “lack of Christian compassion” and said he would continue to place cots and to publicize their availability.

In the still-dark hours of Aug. 28, while the press (and most everyone else) slept, we positioned 4,000 Army troops at Bolling Air Force Base, the Anacostia Naval Air Station and Fort Myer. We stationed Justice Department officials, Army officers and cameras atop the Lincoln Memorial and planted local police, national guardsmen, FBI agents and Army intelligence personnel in civilian clothing among the marchers.

More than 200,000 people arrived by foot, car, bus and train. They walked from the Washington Monument along the reflecting pool to hear speeches from the steps of the Lincoln Memorial.

Vance and I watched apprehensively on televisions in the Army War Room. We were especially concerned about the speech of John Lewis, then-chairman of the Student Nonviolent Coordinating Committee. Lewis had drafted an angry, incendiary attack on the administration for its lack of support. White House aides had pressed Randolph to get Lewis to tone it down. He finally did. His most inflammatory line was, “We want our freedom and we want it now!”

Martin Luther King Jr. delivered his legendary “I have a dream” speech. The marchers conducted themselves peacefully and dispersed late that afternoon, boarding their buses and trains out of the city before dark.

At the Pentagon and the Justice Department, we felt palpable relief. That evening, A. Philip Randolph walked around the grounds of the Lincoln Memorial. He wrote later: “There was nothing but the wind blowing the left over programs and scattered litter across the way.  . . . We were so proud of the fact that no violence had taken place that day. It was the greatest day of my life.” That evening, at age 32, I knew I was at the epicenter of a moral and political revolution.