People who want to be president are not normal. That's what makes Robert Caro's sprawling biography series on Lyndon Johnson so fascinating. Caro is largely sympathetic to Johnson's politics and marvels at his adept political maneuvering. But he is also unafraid to show just how bad a human being Johnson was. Late in the first volume, he sums him up well:
A hallmark of Johnson's career had been a lack of any consistent ideology or principle, in fact of any moral foundation whatsoever -- a willingness to march with any ally who could help his personal advancement.
-Robert Caro, The Years of Lyndon Johnson: The Path to Power, p. 663.
Similar sentiments apply to both 2012 candidates. Power. Always power. Caro's books are about that at least as much as they are about LBJ, their nominal subject. And that is why they will always be relevant.