In the delicate days before the Civil War, Congress proposed a 13th amendment that would have prohibited Washington from interfering with slavery in states where it existed.

It was one of many last-ditch efforts to avert war and stem the tide of southern states seceding.

The amendment, known as the "ghost amendment," was signed by President James Buchanan and left for the new president, Abraham Lincoln, to send to governors for their legislatures to ratify.

Lincoln dutifully did so, sending North Carolina's copy to Gov. John Ellis with a cover letter that didn't endorse or oppose the constitutional amendment.

Last week, 145 years later, editors of Lincoln's papers discovered it among Ellis' documents in the state archives in Raleigh.

It will be on display today at the archives, then will be placed into a vault with other important documents.

"We had two documents with Lincoln's signature, but were surprised and obviously delighted to discover we have a third," said Jeffrey Crow, deputy secretary of archives and history. "Lincoln doesn't say yea, or nay, but it is clearly a part of a larger effort to try to prevent civil war.

"He didn't make emancipation of the slaves a goal of the war until late 1862."

Crow calls the rare and valuable document the "evil twin" of the 13th Amendment that abolished slavery four years later.

But its intention was consistent with the Republican Party's platform of 1860 and what Lincoln said on the campaign trail, said Daniel Stowell, editor and director of the Papers of Abraham Lincoln in Springfield, Ill.

"Lincoln and the Republicans had no intention of interfering with slavery in states where it existed," Stowell said. "They wanted to prevent the spread of slavery into the new territories."

Needing three-quarters of the states to ratify, the proposed amendment was approved by only two states before the war began -- and it was forgotten.

Stowell and colleague Kelley Boston have spent two years scouring archives across the country for Lincoln's papers. They routinely go through the papers of governors.

Ellis' copy is the fifth they've found, with the signatures of Lincoln and Secretary of State William Seward.

"This is certainly one of our most important documents, if just for Lincoln's signature," Crow said. "And to think we didn't even know we had it. That was a big discovery."