"Younger people should realize this is long before cellphones, e-mail or texting," Rosenthal said. "The only way to communicate was by a few precious walkie-talkies or by making personal observations and then hoofing it back to the Justice Department."

One of those on the other end of the walkie-talkies was RFK's assistant, William vanden Heuvel. He was part of a team of "rovers" dispatched by the Justice Department.

"I was close up by the memorial itself, walking that area, so I had a pretty good overview of the program as it proceeded," vanden Heuvel recalled.

"You know, (to) make sure things didn't get difficult or things didn't go in a bad direction. And if they did, just try to intervene."

This was far from the only precaution the federal government took that day. Bars were closed, the National Guard was on standby: The government was prepared for the worst.

"They had a draft drawn up declaring martial law," said Roger Mudd, who anchored the event for CBS.

Every little detail was analyzed, including John Lewis' speech, the contents of which had been released to the press the night before.

"I received a note from Bayard Rustin, saying, in effect, that there was some concern about my speech," Lewis recalled. "Archbishop (Patrick) O'Boyle, who's very close to the Kennedy family, said he will refuse to give the invocation if I didn't change the speech."

Lewis' original draft questioned which side the federal government was on, which would have greatly embarrassed the Kennedy administration.

"The Kennedy administration was using the archbishop as a conduit to express its views," march planner Courtland Cox said.

O'Boyle wasn't the only one to apply pressure to Lewis that day to get him to change his speech.

Reuther, the UAW leader who had been working on behalf of the Kennedys to steer the march to their liking, also joined in denouncing Lewis' proposed speech.

"If John Lewis feels strongly that he wants to make this speech, he can go someplace else and make it," Reuther recalled later. "But he has no right to make it here because if he tries to make it, he destroys the integrity of our coalition."

So after more cajoling from A. Philip Randolph, Lewis and Cox made the necessary changes to his speech on a small typewriter underneath the Lincoln Memorial.

Reuther then called O'Boyle to inform him that the changes were made, and government vehicles were sent to get the bishop through the crowds and to the steps of the Lincoln Memorial.

"I never saw a bishop look so good in my life," Reuther quipped.

Even if Lewis' speech hadn't been changed, there is reason to believe no one would have heard its more fiery contents anyway. The Kennedy administration had the ultimate trump card, and perhaps its most calculating plan in place that day: control of the sound system's on-off switch.

After the final speech by King, those hunkered down in the Justice Department command center in room 5110 didn't relax, despite the fact that there were no outbreaks of violence.

"When the speaking stopped and people started to disperse, there was still the danger of some spark being lit as people were leaving," Rosenthal said

Simultaneously, in another part of Washington, President Kennedy was congratulating the march leaders on a near-flawless event. He couldn't help but already declare the day a success.

"After the March on Washington was over, President Kennedy had invited us back down to the White House," Lewis said. "He stood in the door of the Oval Office and he greeted each one of us. He was like a beaming, proud father. He was so pleased. So happy that everything had gone so well."

President Kennedy even had a message for King after his historic speech: "(Kennedy said) 'And you had a dream,'" added Lewis.

President Kennedy's assassination three months after the march raised fears that the civil rights movement would stall, but the next year, Congress passed the Civil Rights Act of 1964 and President Lyndon Johnson signed it into law. In 1968, assassins would claim the lives of King and Robert Kennedy.

As the nation reflects on the 50th anniversary of the March on Washington, which paved the way for an end to segregationist laws, Rosenthal reflected on the sometimes contentious and evolving relationship the Kennedy brothers had with the march and concluded, "The civil rights movement would not have been as successful when it was, had it not been for the work of the Kennedy administration."