Team of Rivals: The Political Genius of Abraham Lincoln,

His book on Lincoln is not only a classic in the field ... it is a treasured resource,

he may be able to say something good in the weeks ahead, but at least as it appears right now, that moment that calls for the president has passed.

When I first began working on my Lincoln book, nearly a decade ago, he generously invited me to his home so I could peruse his fabulous Lincoln library. He sat with me for hours, suggesting which sources were the most important to begin my journey.

They all start competing against Lincoln as the greatest president. And the [library] building becomes the symbol, the memorial to that dream.

These are the kinds of moments when a president gives voice to the country. They're remembered forever, if it's done right.