Lincoln's Use of Constitutive Metaphors

What is the role of metaphor in Lincoln's major public addresses? My position is that metaphor is central to these speeches, that it constitutes their persuasive core. Lincoln uses such metaphors to mobilize deep-seated, shared values and their concomitant emotional resonances. He does so in the interest of creating a social and political reality worthy of the founders and the American people. The tapping of these resources is a reaffirmation of nationhood as a common enterprise founded in a common past.