The story
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A member of the cabinet who stays at a physically distant, secure, and undisclosed location when the president and all those in the line of succession are gathered at a single location, so as to provide a successor should a catastrophic event occur where the others die or are incapacitated. Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.