Final answer:
President Lincoln signed his full name on the Emancipation Proclamation as a formal and unequivocal endorsement of the executive order, showcasing his commitment to emancipation and to leverage his commander-in-chief authority to avoid legal challenges.
Step-by-step explanation:
On January 1, 1863, President Abraham Lincoln signed the Emancipation Proclamation, which declared that all persons held as slaves in the Confederate States were to be freed. Lincoln used his authority as commander-in-chief to issue the proclamation, understanding it as a measure that could provoke legal challenges. By signing his full name 'Abraham Lincoln' on the proclamation, he was signaling the formal and unequivocal nature of this executive order, underscoring the gravity and official character of the act. This was not merely a scribble; it was a declaration by the highest authority in the nation. Moreover, the signing of his full name gave the document a personal touch, indicating his personal commitment to the cause of emancipation. It should be noted that the proclamation strategically applied only to states in rebellion, as areas occupied by Union troops were not addressed, thereby avoiding immediate contention with slave owners in those regions.