American Enterprise Institute, 2009.

Excerpt:

More has been written about Abraham Lincoln than of any other president or, for that matter, any other American; the amount is prodigious: no fewer than 16,000 books and goodness knows how many journal articles. I cannot claim to have read more than a portion of this vast literature, and I very much doubt that I can say anything about Lincoln that has not already been said by someone, somewhere, sometime. Yet I am obliged to say something.

What accounts for the extraordinary interest in him? Well, he was an extraordinary man; he did things ordinary men don’t do.

Online:
AEI Program on American Citizenship
Rowman & Littlefield [pdf]