Only five known copies of the Gettysburg Address bear Abraham Lincoln’s handwriting. One sits beneath the Abraham Lincoln Presidential Library and Museum in Springfield, Ill., for much of the year, in a vault where the humidity and temperature are tightly controlled.

But on June 15, 2018, those two weathered pages could be found in Glenn Beck’s office.

“Are they requiring you wear gloves?” Mr. Beck, the conservative radio host, asked an archivist who worked for a museum run by his charity, Mercury One. “That’s so stupid.”

Mr. Beck joked to the archivist about spilling chocolate sauce on the framed papers as he sat next to a black box containing the document, which has been valued at $20 million.