OVER THE YEARS, an army of statues has been deployed in the parks, circles and squares of the nation’s capital, many of them commemorating men who played a role in what should have been the liberation of the African people in America. But the fervent hope that accompanied the end of slavery in this country was betrayed over subsequent decades. The newest monument honors the man who rekindled that hope with his insistence, a century after the Civil War, on freedom, equality and nonviolent change.

The Rev. Martin Luther King Jr.’s message was delivered most memorably on Aug. 28, 1963, on the steps of the Lincoln Memorial. The 1963 March on Washington was testimony to how Abraham Lincoln’s vision had been betrayed, how freedom for black Americans had been stifled and stunted, in the century since his Gettysburg Address. The man who succeeded the martyred Lincoln as president, Andrew Johnson, proclaimed, “This is a country for white men,” and then set about to prove he meant it.

He had a lot of help, South and North. Nearly every promise made to a newly freed people was broken. New forms of peonage took root in the South, and basic rights set forth in the Constitution were denied. The Union generals who fought the Civil War, it seemed, had won few hearts and minds; some were themselves avowed racial bigots. It was Martin Luther King’s great insight that a different kind of war had to be fought in this long and agonizing struggle, with the primary weapons being persuasion and an appeal not only to conscience but also to the founding principles of a nation that prides itself on its devotion to equal justice under law.

It’s easy to forget that there was considerable apprehension in the nation’s capital on that morning in 1963. Washington was a largely segregated city, ruled by conservative Southern congressmen and unused to mass demonstrations at the very heart of government. But as the day unfolded and much of the nation watched on television, the huge crowd presented a reassuring picture of peaceable, righteous advocacy, and by the time Dr. King spoke, there was a palpable feeling of goodwill. The words spoken by the young preacher — a man unknown to many and seen as little more than a troublemaker by others — are now in stone, but they will probably never again wield quite as much power as they did on that late August day.

No one can say just how much the March on Washington contributed to the events that followed in the next few years: the series of federal laws, mostly shepherded through by another President Johnson, that sought to guarantee African Americans’ access to public accommodations, housing, employment and the vote, among other things. Surely it helped focus attention on grievances long neglected, and it gave them a greater claim on the national consciousness.

There is now a national holiday honoring Martin Luther King, but this new memorial by the Tidal Basin will have meaning beyond a Monday off in January. It will be a place for pilgrimages by many (not only Americans but also visitors from throughout the world), a site for reflection and contemplation, and a source of pride for those whom Dr. King helped along on a road that still has some distance to be traveled. Unlike the Civil War monuments scattered around town, this one honors not just a heroic figure but his ideals — ideals that helped mend the wrongs of American history and that inspired people throughout the world.