Yesterday, millions of Americans paused to reflect on how 40 years have done nothing to diminish the inspired power of the Rev. Martin Luther King Jr.’s famous speech before the Lincoln Memorial in August of 1963, at the conclusion of what he described as “the greatest demonstration for freedom in the history of our nation.” Coming as it did nearly a decade after the Brown v. Board of Education Supreme Court decision, which had struck an early, crucial blow against legalized racial segregation, the March on Washington was a kind of national convention for a great many unsung heroes around the nation. In tiny rural hamlets and urban centers across the South, men and women began attempting, at great personal peril, to assert basic rights in the face of organized hostility and even mob violence.

The March on Washington had its origins in 1941, when Asa Randolph, the legendary organizer of the Brotherhood of Sleeping Car Porters, threatened a massive demonstration in the nation’s capital to dramatize the unequal working conditions facing black Americans employed by war contractors. That march never took place because President Franklin Roosevelt capitulated to Randolph’s demands and created the Fair Employment Practice Committee, which from 1941 to 1946 investigated — and often remedied — more than 14,000 complaints of discriminatory workplace conditions in the defense industry and the federal government.

Twenty-two years after the aborted march, King and the anti-segregation movement took up the idea again, converging on Washington to demand citizenship rights for black Americans. “When the architects of our great republic wrote the magnificent words of the Constitution and the Declaration of Independence, they were signing a promissory note to which every American was to fall heir,” said King, in words that echoed across the mall and the nation. “This note was a promise that all men, yes, black men as well as white men, would be guaranteed to the inalienable rights of life, liberty, and the pursuit of happiness.”

The well-known theme of King’s peroration was an act of rededication and morale-boosting for members of the rapidly growing civil rights movement. For the nation, the speech was a call to renewal. “I have a dream that one day this nation will rise up and live out the true meaning of its creed. We hold these truths to be self-evident, that all men are created equal,” King said, in words that will last as long as the republic. “With this faith we will be able to transform the jangling discords of our nation into a beautiful symphony of brotherhood. With this faith we will be able to work together, to pray together, to struggle together, to go to jail together, to climb up for freedom together, knowing that we will be free one day.”