Abraham Lincoln’s Gettysburg Address has inspired people for generations, but a new book claims to show startling racial contradictions on the part of the president, including covert colonisation talks with Britain.

As the nation celebrates the 150th anniversary of Lincoln’s first inauguration, the book by a researcher at George Mason University in Fairfax said Lincoln was even more committed to colonising blacks than previously known.

Colonisation After Emancipation is based in part on newly-uncovered documents that authors Philip Magness and Sebastian Page found at the British National Archives outside London and in the US National Archives.

The authors cite jarring remarks made by Lincoln in 1862 to a White House audience of free blacks, urging them to leave the US and settle in Central America.

“For the sake of your race, you should sacrifice something of your present comfort for the purpose of being as grand in that respect as the white people,” Lincoln said, promoting his idea of colonisation - resettling blacks in foreign countries in the belief that whites and blacks could not co-exist in the same nation.

Lincoln went on to say that free blacks who envisaged a permanent life in the US were being “selfish” and he promoted Central America as an ideal location “especially because of the similarity of climate with your native land - thus being suited to your physical condition”.

In an interview, Mr Magness says he thinks the documents he uncovered reveal Lincoln’s complexity.

“It makes his life more interesting, his racial legacy more controversial,” said Mr Magness, who is also an adjunct professor at American University.

Lincoln’s views about colonisation are well known among historians, even if they do not make it into most school books. Lincoln even referred to colonisation in the preliminary Emancipation Proclamation, his September 1862 warning to the South that he would free all slaves in Southern territory if the rebellion continued.

Unlike some others, Lincoln always promoted voluntary colonisation, rather than forcing blacks to leave. But historians differ on whether he moved away from colonisation after he issued the official Emancipation Proclamation on January 1st 1863, or continued to support it.

Mr Magness and Mr Page’s book offers evidence that Lincoln continued to support colonisation, engaging in secret diplomacy with Britain to establish a colony in British Honduras, now Belize.

Among the records found at the British archives is an 1863 order from Lincoln granting a British agent permission to recruit volunteers for a Belize colony.

“He didn’t let colonisation die off. He became very active in promoting it in the private sphere, through diplomatic channels,” Mr Magness said. He surmises that Lincoln grew weary of the controversy that surrounded colonisation efforts, which had become enmeshed in scandal and were criticised by many abolitionists.

As late as 1864, Mr Magness found a notation that Lincoln asked the attorney general whether he could continue to receive counsel from James Mitchell, his colonisation commissioner, even after Congress had eliminated funding for Mr Mitchell’s office.

Illinois’ state historian, Tom Schwartz, who is also a research director at the Abraham Lincoln Presidential Library in Springfield, said that while historians differed, there was ample evidence that Lincoln’s views evolved away from colonisation in the final two years of the Civil War.

He said Lincoln gave several speeches referring to the rights blacks had earned as they enlisted in the Union Army, for instance. And presidential secretary John Hay wrote in July 1864 that Lincoln had “sloughed off” colonisation.

“Most of the evidence points to the idea that Lincoln is looking at other ways” to resolve the transition from slavery besides colonisation at the end of his presidency, Mr Schwartz said.

Lincoln is the not the only president whose views on race relations and slavery were more complex and less idealistic than children’s storybook histories suggest.

George Washington and Thomas Jefferson were both slaveholders despite misgivings. Washington freed his slaves when he died.

“Washington, because he wanted to keep the union, knew he had to ignore the slavery problem because it would have torn the country apart, said James Rees, director of Washington’s Mount Vernon estate.

“It’s tempting to wish he had tried. The nation had more chance of dealing with slavery with Washington than with anyone else,” he added, noting the esteem in which Washington was held in both the North and the South.

AP