The writing instrument favored by the former President of the United States for formal document signings is a personalized Sharpie marker. These markers are typically black, with a felt tip, and known for producing a bold line.
The choice of this specific writing tool carries both practical and symbolic weight. The Sharpie provides a broad, highly visible signature, which photographs well and is easily recognizable. Furthermore, the decisiveness associated with a bold, permanent line may project an image of strength and resolve. This practice, though seemingly simple, has become a characteristic element of public events involving official endorsements.