"An Excerpt from Lincoln's Greatness." Interpretation 8.2,3 (May 1980): 22-25. Also in "With Firmness in the Right...: Two Addresses on Abraham Lincoln" Claremont: Claremont Men's College, 1960. 15-21.

In this portion of a speech originally published by Claremont Men’s College in 1960 and reprinted in an issue of Interpretation in 1980, Diamond suggests that the greatness we attribute to Abraham Lincoln was not so much produced by the American regime as permitted by it. Nonetheless, that a man of Lincoln’s excellence should have appeared among us and been accorded the highest political office, Diamond argues, is a profound tribute to our regime’s commitment to a restrained, moderate understanding of democracy and equality.

Online:
Interpretation: A Journal of Political Philosophy [pdf]
Google Books
AEI Program on American Citizenship [pdf]