During his now-famous “I Have a Dream” speech at the March on Washington, the Rev. Martin Luther King Jr. referred to the Emancipation Proclamation that freed millions of slaves in 1863. But, he insisted, a hundred years later “… the Negro is still not free.”

Today, we’re celebrating the birth of the civil rights leader a few weeks after marking the 150th anniversary of the Emancipation Proclamation.

This year also marks the 50th anniversary of the March on Washington, which took place Aug. 28, 1963, and the “Letter from Birmingham City Jail,” an open letter King wrote on April 16, 1963. In that letter, King wrote that “one has a moral responsibility to disobey unjust laws.”

A scholarly King understood the impact of history and reflection. It wasn’t an accident that the March on Washington, attended by 250,000 people and to that point the largest demonstration the nation’s capital had seen, occurred 100 years after the Emancipation Proclamation.

There was a widespread belief among marchers, some carrying signs reading “Free by ’63,” that a century was long enough to wait for the realization of the rights that were granted to the ex-slaves. King stressed the point at the beginning of his 17-minute speech, that a hundred years had made little difference in the lives of a significant portion of Americans. In the extemporaneous ending to the speech, King said, in part:

“I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin, but by the content of their character.”

And now?

According to Clayborne Carson, director and senior editor of the King Papers Project at Stanford University, the civil rights leader would recognize elements of progress, always stressing the importance of celebration, but also acknowledging how much further we have to go.

He would be upset about the way in which some Americans celebrate his “I Have a Dream” speech as if it were in the past tense – that it had already been achieved when in reality, at the time of his April 4, 1968, assassination he often spoke of his unfulfilled dream. King’s goals were still out in the future and, by many accounts, remain in the future, as there is still the poverty and war he fought against at the end of his life.

A half-century on from the March on Washington and a full 150 years following the Emancipation Proclamation, this nation has an African-American president who has just won election to a second term and today is being inaugurated. Could King have envisioned such an achievement, or the fact that today this nation is celebrating his own birth, and does so as a national holiday?

Carson’s book, “Martin’s Dream: My Journey and the Legacy of Martin Luther King Jr.,” makes the point that as a presidential candidate, Barack Obama continued King’s dialogue with “the architects of our republic” about the meaning of the American Dream: “He drew inspiration from an American tradition of democratic thought that extended back through King to Lincoln, whose great speech at Gettysburg provided a template for King’s prepared remarks at the March on Washington, and then to Jefferson.”

As the Stanford University author so eloquently added, “Both King and Lincoln recognized that the nation’s destructive racial divisions could be bridged only if Americans resolved to make real the promise of universal human rights that justified their nation’s Declaration of Independence.”

Now, 150 years after the signing of the Emancipation Proclamation and 50 years after the March on Washington, it is time to celebrate the birth of the civil rights leader. His life was taken early, but not before making an impact on the nation and world. King’s legacy will live on long into the future.