NEW YORK – “Neither slavery nor involuntary servitude…shall exist within the United States.” The language of the 13th Amendment is as powerful and memorable as the President who signed it. Two years earlier, Abraham Lincoln had declared enslaved people in Confederate territory “forever free” in his Emancipation Proclamation. “It will be for this act,” said Lincoln at the time, “that my name goes into history.” Today, the 16th president continues to captivate the American imagination, and his legacy looms large over our political and popular culture. One of the foremost scholars of the brilliant politician is historian Harold Holzer, a prolific and award-winning author who served as a script consultant on Steven Spielberg’s Oscar-nominated film Lincoln. As rare, contemporaneous copies of the Emancipation Proclamation and 13th Amendment, signed by Lincoln himself, come to auction at Sotheby’s on 25 May, we spoke with Holzer about the enduring significance of the documents, their impact on history and Lincoln’s reputation as a civil rights defender.

LINCOLN SCHOLAR HAROLD HOLZER. PHOTOGRAPH BY DON POLLARD.

You have spent much of your career studying Lincoln's presidency. Could you share one of the most surprising facts you've discovered?
Lincoln may have been a humble, amusing, homespun fellow, but he was also a killer politician, and a brilliant image-crafter. We think of him principally as a great orator, and of course he was. But his reading audiences far outnumbered his hearing audiences and he knew that more people saw him in photographs and prints than could ever see him in the flesh, so he relentlessly pursued press attention during his rise to power in the 1850s and beyond. He was his own press secretary, and a damn good one – at one point he even secretly purchased a German-language Illinois weekly (which he could not read!) so it could push the Republican agenda to immigrant voters in the west. Though he insisted that he was “the homeliest man in Illinois,” he made himself available with astonishing frequency to painters, sculptors and photographers prepared to romanticize his image.

What are some of the biggest misconceptions about Lincoln as a civil rights figure? And what does history tend to get right?
For years, historians oversimplified Lincoln as “the man who freed the slaves.” Then, after the Civil Rights movement a century later, the pendulum swung to such a sharp degree that some now question Lincoln’s sincerity as a progressive freedom-fighter. Both extremes are ridiculous. It is true that Lincoln was not the most liberal rights advocate in America of his time – Frederick Douglass was more so, of course – but Lincoln was the electable one exercised his power to destroy slavery. As for equal rights, he was a gradualist, which is why he was able to win national elections in an innately cautious and deeply racist country. Had Lincoln lived, I think he would have moved slowly (but also surely) to secure voting and civil rights for free African Americans. We owe it to Lincoln to judge his achievements and sacrifices by the standards of his century, not ours. Remember, John Wilkes Booth heard Lincoln call for black voting rights and vowed then and there it would be the last speech the President ever made. Three days later, Booth shot him. Lincoln literally died for civil rights.

AN EXTREMELY RARE MANUSCRIPT COPY OF THE THIRTEENTH AMENDMENT TO THE UNITED STATES CONSTITUTION, SIGNED AND ENDORSED BY ABRAHAM LINCOLN. ESTIMATE $2,000,000–3,000,000.

Steven Spielberg’s Lincoln portrays the President as willing to resort to some unexpected tactics when it comes to the passage of the 13th Amendment. How close does this depiction come to reality?
Spielberg’s depiction of the passage of the House resolution sending the 13th Amendment to the states was pretty colourful, but not really overblown. Of course, many details were created for cinematic purposes only: Lincoln didn’t go door-to-door securing Congressional approval, as the film showed. Mary Lincoln did not sit in the House gallery counting votes, and I doubt whether the President visited the seedy boarding house where the New York lobbyists resided, to give them instructions on which Congressmen could be bought off to switch their votes from “no” to “aye.” But the Lincoln Administration undoubtedly played a role in twisting arms, proffering government jobs and maybe even tolerating some cash giveaways to get that resolution passed.

What were the most significant impacts of the Emancipation Proclamation and 13th Amendment on the United States?
The Emancipation Proclamation redefined the rationale for the Civil War into a crusade for freedom – a new Union truly “dedicated to the proposition that all men are created equal,” as Lincoln reminded his listeners at Gettysburg. The proclamation gave the Union army the power to free slaves wherever they marched. It gave enslaved people themselves the impetus to flee on their own, and it swelled the army with new black recruits. Of course, then as now, Presidents worry what their successors will do about their executive orders, and Lincoln ardently believed that his initiative needed to be consecrated by ridding the Constitution of its most horrific flaw. The 13th Amendment “put the harpoon in the monster,” as Lincoln put it, killing slavery everywhere, even in border slave states that had remained loyal to the Union.

THE "AUTHORIZED EDITION" OF THE EMANCIPATION PROCLAMATION, SIGNED BY PRESIDENT ABRAHAM LINCOLN. ESTIMATE $1,500,000–2,000,000.

Did Lincoln realize the huge importance of these documents at the time?
He knew the historic value of the documents, and made certain he would always be associated with both. He would not sign the final Emancipation Proclamation until he was sure that his right hand, “almost paralyzed” from New Year’s Day hand-shaking, felt strong enough to make certain that his signature would not look “tremulous,” as if he doubted his authority to liberate slaves in Confederate territory. “If my name ever goes into history,” he said at the time, “it will be for this act,” and he did not want anyone to think he “hesitated.” And when the House Resolution authorizing the states to vote on the 13th Amendment came to his desk two years later, he similarly signed it with a bold hand. In this case, his approval wasn’t even legally required, and a few senators were so upset that Lincoln had added his signature that they proposed a resolution condemning him for trying to share the credit. Did Lincoln want history to acknowledge his role in the constitutional amendment? You bet he did.

Harold Holzer was appointed by President Bill Clinton to chair the United States Abraham Lincoln Bicentennial Commission. After winning the Lincoln Prize plus awards from Columbia and Harvard for his recent Lincoln and the Power of the Press, his next book, due out in 2018, will be a biography of Lincoln Memorial sculptor Daniel Chester French.