Jefferson Davis is on the cover of the book because Jefferson Davis is included in the book. Why? Because I consider Jefferson Davis an American President — not a President of the United States, but an American President. I’ve explained my reasoning behind that many times here on the website and there is also an explanation in Tributes and Trash Talk.
The reason that Davis is placed where he is on the cover (after Obama) is because, while I include him in the book and consider him an American President, Davis doesn’t fit in the Washington-to-Obama lineage. I didn’t want him to be on the top line of the cover in front of Washington, so he comes in at the end. That’s where his chapter is in the book, as well — at the end, after Obama, outside of the Washington-to-Obama lineage.