Lousy wording. "Essential" President Bush presupposes the existence of a nonessential one as well, and such dubious thinking is for DU.
That's silly.
It's a common formulation, indicating a look at the essence of a subject or person, as in: "The Essential C.S. Lewis" or "The Essential Plato." If an author were to write "The Great George Washingon," that would not "presuppose" the existence of a non-great Washington.