At the time of his death, Abraham Lincoln was enshrined in the public mind as "The Great Emancipator," a reference to what most Americans then considered the most hallowed of his accomplishments as president: writing and signing the Emancipation Proclamation, which freed the slaves.

Lincoln issued the Proclamation without seeking the advice of his own Cabinet, and bypassed the squabbling Congress by making it an order to the Army and Navy from their commander in chief. The act was such a perfect expression of his political will that it passed into history with little of the drama surrounding the 13th Amendment to the Constitution.

That may explain why the Emancipation Proclamation -- as celebrated as it was at the time -- receives only passing mention in "Lincoln," Steven Spielberg's portrayal of the 16th president's tireless campaign to remove the monstrous moral stain the Founding Fathers had left on the Constitution. And it helps explain why the Proclamation will mark its 150th anniversary Tuesday with little fanfare, despite its towering role in American history.

The film instead details the consuming struggle that played out two years later, when Lincoln moved to enshrine the end of slavery in near-immutable law. But it was the Proclamation, not the 13th Amendment, that remade Lincoln's objective in the Civil War, from putting the Union back together as it had been before 1861, to creating a new nation in which slavery was abolished.

"You never would have had the 13th Amendment without the Emancipation Proclamation," points out Steven Millner, professor of African-American studies at San Jose State. "It was a nation-saving act, a turning point in our evolution."

Preaching at a Brooklyn, N.Y., church the night the historic document was signed, abolitionist Henry Ward Beecher summarized what Lincoln had done. "The Proclamation may not free a single slave," he said, "but it gives liberty a moral recognition."

Lincoln knew that once word of the Proclamation spread through slave quarters in the South, its effect would be liberating. "I never, in my life, felt more certain that I was doing right," he said, "than I do in signing this paper."

It had taken him and the country "four score and seven years," as he would note later that year in the Gettysburg Address, to undo America's original sin. But the Southern slaves Lincoln sought to set free by fiat would remain in bondage for another two years -- until the Confederacy surrendered.

Black churches in the nation's capital, and throughout the North, had spent New Year's Eve in 1862 praying that Lincoln would not rescind the draft he had released three months earlier, promising to make slaves in the 10 Confederate states "forever free." When the executive order came, church bells pealed in wild celebration. Freedom is the thing that rings, and 150 years ago, it rang in the new year.

At Gettysburg, Lincoln would proclaim that "this nation, under God, shall have a new birth of freedom," and with the Proclamation, he set that rebirth in motion -- though he may have overstepped his constitutional authority in the process. If Southerners had sued after the Civil War to reclaim their slaves, declaring them lost property, "they may have had an excellent chance to win that kind of lawsuit in a federal judiciary that had announced Dred Scott in 1857," Millner said. "It would have been a complete disaster if a judicial ruling had usurped the Emancipation Proclamation, but in theory it could have happened. It just points to the genius of Lincoln."

Lincoln often went to the telegraph office at the War Department seeking -- of all things -- peace and quiet, and that's where he composed most of the Proclamation. It was written in the legalese familiar to him as a former country lawyer in Illinois, not the lofty rhetoric he summoned for public speaking. Most of what it said would have been incomprehensible to the slaves it was meant to set free.

The Proclamation was intended to give slaves a reason to run away, and before the end of the war, nearly 200,000 of them enlisted in the fight to secure their people's freedom. But even after the 13th Amendment was ratified and the war was over, real emancipation came slowly for 4 million freed slaves, most of whom had known only servitude.

"The majority of them stayed right where they were," said Donna Wyant Howell, a Washington, D.C.-based researcher who compiled their narratives for a book, "American Slaves," using material collected by the Works Progress Administration during the 1930s. "They didn't have any money. They didn't have any possessions other than the clothes on their backs. So they raised the crops and depended on their former owner to pay them half the value of the crops every year. But they couldn't read, they couldn't write and they didn't know the value of money."

For at least a century, black churches celebrated the Emancipation Proclamation with services on the anniversary of its signing, and it held pride of place on the calendar over passage of the 13th Amendment. But on this sesquicentennial, President Barack Obama -- the first African-American to serve in the same office once held by the Great Emancipator -- is not scheduled to mark the Proclamation's anniversary in any way.

Contact Bruce Newman at 408-920-5004. Follow him at Twitter.com/BruceNewmanTwit.

To learn more

Two books commemorating the 150th anniversary of the Emancipation Proclamation recently went on sale. The firsthand narratives recorded in "American Slaves" are available at AmericanSlaves.com, or by calling 888-752-8379. A collection of photos documenting the lives of African-American slaves and free men at the time of the Proclamation, "Envisioning Emancipation: Black Americans and the End of Slavery" is in bookstores and available online.

Proclamation celebration

An observance to mark the Emancipation Proclamation's 150th anniversary will take place at the Bayview Opera House in the Ruth Williams Theatre, 4705 Third St., San Francisco. The program runs from 2-4 p.m., and details are available at 415-824-0386.