A meeting with the president. A bomb threat that evacuated his plane. An FBI campaign to destroy his credibility: Fifty years ago this week, Martin Luther King, Jr. had a lot on his plate.

But the biggest thing, gaining steam as he watched, was now beyond his power to shape.

In early 1964, legislation that King had worked for, to desegregate daily life in America, was finally about to march through Congress.

As President Lyndon B. Johnson and legislators maneuvered in the coming months, King watched from outside. And King made sure that they could watch him, leading protests, speaking about the bill, getting arrested, and spotlighting inequity to keep up pressure for congressional action.

For years now King holidays have provided Americans moments of reflection and service (or just a day off work). This year’s isn’t just any King holiday. It marks a half-century since the passage of the Civil Rights Act of 1964, the first of the sweeping federal statutes to make the movement’s values the law of the land.

The act, signed into law on July 2, made it illegal to segregate public accommodations like hotels, theaters and lunch counters, and it outlawed discrimination in most employment. It also set the stage for the Voting Rights Act of 1965.

The environment King helped create — especially the riveting spectacle of the March on Washington in August, 1963 — had set the stage. After the march and the protests in Birmingham, Ala., a groundswell of public support moved the bill forward, said Vicki Crawford, director of the King Collection at Morehouse College, where King got his sociology degree.

But where 1963 was about potent symbolism and appeals to conscience, 1964 was largely about insider politics and the mechanics of congressional power.

And, as Crawford said, “The thing about the Civil Rights Act is, (King) wasn’t a legislator.”

Even if King had wanted to lobby Congress, he wouldn’t have helped with the conservative white legislators that needed to be swayed, said David Garrow, author of the history “Bearing the Cross.” In any case, Garrow said in an interview, “It’s not like King has any time on his hands to think about: What can I do to help the bill get through?”

The assassination of John F. Kennedy in November, 1963, just months after King electrified much of the nation with his “I Have a Dream” speech, brought fear that the civil rights bill, already on shaky ground, would founder. But addressing the nation after the assassination, President Johnson painted the bill as Kennedy’s legacy, and it caught fire.

During winter recess, many congressmen saw that the bill had their voters’ support. When they came back to work in January, the committee chairman from Virginia who was holding the act prisoner in the House had to loosen his clutches and let it go to debate, where it soon passed that chamber.

At the same time, the FBI working overtime to destroy King’s legacy. Fearing that he was influenced by communists, the bureau had started bugging his rooms and telephones. In January, agents recorded King in a sexual indiscretion at Washington’s Willard Hotel and determined to “reduce him completely in influence,” according to the history “Pillar of Fire” by Taylor Branch. FBI director J. Edgar Hoover had his staff bypass Attorney General Robert Kennedy, who might have warned King, and show the report directly to President Johnson.

But if Hoover wanted the tape to offend a president, he picked the wrong president. Instead of disowning King, three days later Johnson summoned King and some colleagues to a private sit-down, and the White House announced the invitation to reporters.

A group led by Georgia’s Richard B. Russell fought and stalled the bill in the Senate. King gave sermons at his home base in Atlanta, spoke at protest meetings across the South, and flew across the country to raise money.

King tried to vacation in Hawaii, monitored by a five-man FBI surveillance team. As Russell’s forces filibustered the bill for two months, King told colleagues he might go on a fast to create pressure for its passage, Garrow wrote.

With summer approaching, protests in St. Augustine, Fla. took center stage in the movement. King was in St. Augustine the day the Senate finally voted to end the filibuster, June 10.

That evening, he led a protest, and the next day, he decided to get arrested by asking to be served at a segregated motel restaurant and refusing to leave.

Three weeks later, when the Civil Rights Act was signed on July 2, the restaurant owner who had called the police on King now told the press that he and other businessmen had voted to abide by the law. (He subsequently zig-zagged under threats from the Klan, and the restaurant was firebombed).

When the act became law, King “rejoiced with the rest of us,” Joseph Lowery, who co-founded the SCLC with King, said in an interview. (Lowery, by the way, suggests the FBI fabricated the Willard Hotel scene.) There were pockets of resistance, but the part of the law governing access to public accommodations was surprisingly effective right away, Lowery said.

A year later the employment provisions took effect, and gradually came to have an even greater impact, Garrow said.

Larry Spruill, now a professor of history at Morehouse, was a teenager in 1964, growing up poor in New York. “The issue of segregation in hotels or restaurants — that is not the real power of the act. The power of the act is that it really was the federal government being forced to get deeply involved in the issue of civil rights,” Spruill said. “Now you had government and law on your side.”

He added, “My family goes back to the 1760’s in North Carolina. But I am the first college graduate. And that is a result of the civil rights movement. The Civil Rights Act says segregation is formally illegal nationwide.”