One way to think of it is this: It is a page from the script for the script for “Lincoln.”

The script for the script? Historical documents and reference materials served as the basis for the movie’s script, and this is an original document, a 106-word draft of a telegram signed by Abraham Lincoln himself. So it was not polished by the writers in Hollywood.

Lincoln wrote it in May 1862, when, as the movie made clear, Lincoln was focusing on the Emancipation Proclamation. Lincoln sent the telegram — to be displayed at the Winter Antiques Show, which opens to the public on Jan. 25 at the Park Avenue Armory — in reply to a 10-page message from Maj. Gen. George B. McClellan, who has been described by one historian as Lincoln’s “never-ready” general....