Ronald C. White Jr., a Huntington Library fellow and a visiting professor of history at UCLA, is the author of the bestselling books Lincoln's Greatest Speech: The Second Inaugural (a New York Times Notable Book of the Year) and The Eloquent President: A Portrait of Lincoln Through His Words. His latest book A. Lincoln: A Biography (2009) has been a New York Times, Washington Post, and Los Angeles Times bestseller and a History Book Club selection. He is in high demand as a speaker, especially as the Lincoln Bicentennial and Barack Obama's use of the Lincoln Bible for his inauguration have sparked a new wave of interest in the 16th president (see White's article "Linked by a Bible" in the Los Angeles Times).

February 12, 2009, was the 200th anniversary of Abraham Lincoln's birth, and the country is celebrating with numerous bicentennial books and events this year. Why does Lincoln still fascinate us?

Think of the Lincoln story—the humble beginnings, the minimal education. Washington and Jefferson are notable figures in our history, but they're patricians. But Lincoln shows that anybody (in Lincoln's own words) "has the right to rise"—that by character, by hard work, by education, one can rise in this society. Lincoln personifies that American dream.

As you were doing the research for your book, did anything surprise you or change your understanding of Lincoln?

In the Collected Works of Lincoln, which is nine volumes, there are over 125 texts which the editors in the 1950s labeled "fragments." All of these are separated from each other, but I realized that if you brought them together, they almost form an intellectual diary. They are often not dated, but they always begin with a problem: for example, the problem of slavery or the Dred Scott decision, or the formation of the Republican Party. For me, one of the most important one is the so-called "Meditation on the Divine Will," in which Lincoln is asking himself the question, "Where is God in the midst of the Civil War?"

These fragments were found only after Lincoln's death, and because they've remained separated from each other, we have not quite seen that this is the way Lincoln defined himself. He would take these little scraps of paper, sometimes the back of a flap of an envelope, and he would start with a problem. He would brood about it and reflect on it and sometimes do a syllogism. For example, slavery: Why is it that one person can hold another person in slavery? Is it because the first person is more intellectual than the second, or is it because the first person has a greater economic standard than the second, or is it because … ? And he asks all these questions. At the end of this little scrap of paper he writes, "I cannot think of a single reason why one person could hold another person in slavery."

Some of them are very self-revealing—words that Lincoln would never say out loud. In 1856, he's really down on himself. He had run in 1855 for the Illinois Senate and been defeated. So he's writing this note in which he elaborates all the great accomplishments of Stephen Douglas, his erstwhile opponent, and he goes on and on and lists all the things Douglas is, and at the end of the note he says, "My life is nothing but a flat failure." This is the sort of thing you say to yourself but that you don't say to your friends. But it tells us what Lincoln is thinking in 1856. This is a very low point in his life.

I suggest in my biography that this is the way Lincoln defines himself, defines ideas, and ultimately it will be the way he will define and redefine America. Often these ideas become the basis of some later address or public letter. For example, the "Meditation on the Divine Will" is really the intellectual foundation of the Second Inaugural Address. So I argue that Lincoln was not a spontaneous genius who could sit down and with a stroke of the pen write out the Gettysburg Address or the Second Inaugural; rather, he was a person who was taking notes through the years, and when he was ready, these notes became the grist or the foundation for a more public, polished document. Even then, he would go through two, three, four, even five drafts before he was satisfied that he was ready to present it to the public. So I find Lincoln a man of great intellectual curiosity, a person of ideas; but I wanted to know how did these ideas germinate, how did they move from private to public?

Before writing this book, you had written several books on Lincoln's speeches and writings. How did that prior work prepare you for creating a more comprehensive portrait of the president's life and character?

Our culture diminishes words, but words were critical in the 19th century. Lincoln understood the power and meaning of words. Therefore I needed in this biography to continue to examine his words as a key to understanding him. I wanted to see the way Lincoln grew in his speaking, because I argue that this is what separates him from his peers—he rises by his ability to communicate. And I wanted to find out how he developed this great gift of writing and speaking.

You wrote an article for Christian History called "War and the Will of God," in which you showed how Lincoln's Second Inaugural Address revealed the president's belief in divine providence and his nuanced understanding of the nation's sins. Are there other public speeches that give us insights into Lincoln's beliefs?

One surprised me a bit: In 1842, he delivered an address to the Washingtonian Temperance Society in Springfield. The temperance movement was begun by voluntary associations; it was a product of the Second Great Awakening. But the Washingtonian society was secularized and was trying to reform drunkards. Lincoln is very critical of the religious temperance movement because it starts out by criticizing people who drink, and he says you should start out by befriending these people. People never hear you if you criticize them; they only hear you if you are a friend. Then at the end of his address, to make his point clear, he says that it is just like "that Omnipotence" who "condescended to take on himself the form of sinful man, and, as such, to die an ignominious death for their sakes." Well, first of all, the notion that Lincoln never mentioned Jesus is wrong. Here he says that our empathizing with others is based on the model of the Incarnation, of God sending his Son to enter into history. Way back in 1842, when Lincoln is still a long way from the beliefs that he will have in the 1860s, he is already using this analogy of the Incarnation to make his point.

There are other examples. Lincoln offers a Whig circular in 1843, and although signed by five authors, it's clear that Lincoln is the main author. He quotes both Aesop and Jesus to make his point about how Whigs ought to reach out to others. And I would argue that the insertion of those two words "under God" changes the whole meaning of the Gettysburg Address—from the natural to the supernatural. In every copy he made of the Gettysburg address afterwards, he kept that phrase "under God."

Some people would say that these references in his public speeches are simply political rhetoric. He was speaking into a context in which those beliefs were accepted, but these don't necessarily reflect his private beliefs.

That's probably the accepted view. I've had it said to me two ways: First, this is nothing more than what a cultured person would say in the 19th century—you'd quote the Bible (almost as literature) and you'd quote Shakespeare. Or, these are the words of someone who is obviously a shrewd politician, and he is speaking to an audience that he knows is largely a religious audience. So those are the considerations with which I began my work.

Then, fortunately for me, I turned to people who knew Old School Presbyterians even better than I did, and I said, wait a second: Let's look at the text. If you look at the text of the Second Inaugural, you see some words that, as far as I can tell, have never been illuminated before. For example, Lincoln says, "Shall we discern therein any departure from those divine attributes … " Divine attributes—where does that come from? That's a strange way of speaking of God. But not if you're an Old School Presbyterian. Phineas Densmore Gurley (the minister of the church Lincoln attended in Washington D.C.) studied at Princeton Seminary, and his main professor was Charles Hodge. Chapter 3 of the first volume of Hodge's Systematic Theology is "The Divine Attributes of God." Even more telling, chapter 3 of the Westminster Confession of Faith is "The Divine Attributes of God."

Where did Lincoln get this language? This is not "the Bible as literature." This is not what a cultured person would say in the middle of the 19th century. This is exactly what he had been hearing from Gurley at New York Avenue Presbyterian Church. Gurley's sermons have been lying all these years untranscribed in the Presbyterian Historical Society. When Gurley preached the funeral sermon for Lincoln's son Willie, he asked Lincoln to trust in biblical providence. I argue that this is biblical providence mediated to Lincoln through Old School Presbyterian theology.

People make a great mistake when they draw a line of continuity between fatalism and providence or predestination. No 19th century minister or theologian would have ever made that mistake. Fatalism is unbelief, not providence—Christians believe in a personal God who loves us and who acts in history. Fatalism is the God of Thomas Jefferson, who sets the world in motion, but does not intervene.

The point of all this is not that we can exactly quantify Lincoln's faith. We can't put on a grid what he believed about the cross or the resurrection. Lincoln was always changing his mind. But it seems to me that his faith was maturing and developing; he "comes out," so to speak, in his Second Inaugural. And I'm convinced that we would have heard far more about his faith in his second term if he had lived.

One of the problems for historians is that unfortunately some of the people who first wrote about Lincoln in the 19th century wanted to Christianize him—no doubt about that. And other writers sometimes used reminiscences too uncritically. So the professional scholar who comes to this task is understandably wary—and should be.

What do you most want people to understand about Lincoln's beliefs and how they affected his presidency?

First of all, it is misleading not to talk about Lincoln's faith or to obscure his faith. But what we really see in the "Meditation on the Divine Will" is Lincoln's engagement with profound questions of the Christian faith. Here towards the end of his life, we see evidence of the growth of Lincoln. I would argue that the Second Inaugural is the finest expression in all of American history of the deep connection between religion and politics. The private Lincoln in "Meditation on the Divine Will" becomes the public Lincoln in the Second Inaugural.

What can Christians learn from Lincoln about how to talk about faith and politics today?

How to talk humbly, inclusively ("Both read the same Bible and pray to the same God"), pointing beyond ourselves and our own experience ("The Almighty has His own purposes"), being comfortable with some ambiguity ("I'm almost ready to say"), admitting that we don't know it all.

It has been alleged that there is no redemption in the Second Inaugural Address, but there is redemption: "The Almighty has His own purposes," and therefore (there is an unvoiced therefore here) "with malice toward none, with charity for all … " What God has done needs to carry a direct imperative for what we should do. And the model for what we should do is God's self-sacrificing love in his Son, and therefore we should live with malice toward none and charity for all.

Lincoln is a pearl that has been hidden from the Christian community and obscured. We've focused on almost everything else in the Lincoln Bicentennial, but not much on that.