Editor's note: Fox News anchor and former White House Press Secretary Dana Perino recently sat down with Jonathan Horn, author of the new biography on Robert E. Lee, "The Man Who Would Not Be Washington: Robert E. Lee's Civil War and His Decision That Changed American History" (Scribner, January 6, 2015) to talk about the book and its larger lessons.

Dana Perino: How did you come to be so interested in Robert E. Lee's life, and why did you think it was important for people to know more about him?

Jonathan Horn: What first drew me to Robert E. Lee’s story was geography. I grew up near the Potomac, the same river Lee called home. He spent his childhood in the town of Alexandria, which now is part of Virginia but then was part of the District of Columbia. He married his wife at Arlington House, the columned mansion across the Potomac from where the Lincoln Memorial now stands. And at the start of the Civil War, leaders on both sides of the river recruited Lee for high command.  

The more I studied the choice Lee faced in 1861, the more I wanted to tell his story. He faced an agonizing decision between his devotion to the Union and the duty he felt to follow his native state of Virginia into rebellion. We often focus so much on historical movements and trends that we lose sight of how history can pivot on the decision of one individual. Here was such a moment. The decision Lee made forever changed the course of American history.  

Perino: Explain the title: "The Man Who Would Not Be Washington."

We remember George Washington as the man who would not be king. The title of my book plays off that phrase and speaks to a tragic tension in Lee’s life: that one decision could turn an army officer so closely bound to George Washington’s family against the Union that represented Washington’s greatest legacy. 

For generations, Washingtons and Lees had lived along the Potomac. Lee’s father was Washington’s most famous eulogist, author of the famous words “first in war, first in peace, and first in the hearts of his countrymen.” Meanwhile, Lee’s father-in-law was George Washington’s adopted son.

These connections were so powerful at the start of the Civil War that an emissary for the Lincoln administration actually tried to persuade Lee to accept command of the main Union army by arguing that the country looked to Lee as “the representative of the Washington family.” Lee’s place in history today would be very different had he accepted that offer instead of casting his fate with Virginia.

Perino: Is there anything in your new book that we may not have known before?

Researching this book revealed just how fraught the Washington-Lee relationship was. For example, what most entangled Lee in slavery—the institution that caused the Civil War—was his marriage to the daughter of George Washington’s adopted son. Lee spent a few years before the war actively managing an estate that included slaves descended from George Washington’s Mount Vernon plantation.

The decision Lee made to fight against the Union tore his ties to its founder in shockingly personal ways that I think will astonish readers, even history buffs who already know something of how federal authorities captured and converted the Arlington estate, where Lee married, into the cemetery we know today.

Perino: During your extensive research, you seem to come to know Lee personally, noting that he had a sense of humor. What was it like to delve so deep into the libraries and archives to piece together the characteristics of someone from another place and time?

Poring over 19th century correspondence makes you feel grateful to the family members and archivists who preserved these documents. It also makes you feel privileged because Lee’s personal letters, like our emails today, express feelings and thoughts that he never intended to share with the public. 

You quickly realize that historical figures defy the simple ways we often characterize them. 

It is true that Lee had a sense of humor, but he also suffered from fatalistic gloom. A general widely remembered for his ability to seize the initiative on the battlefield privately believed himself a captive of circumstance.

Perino: Given all that you learned about Lee and the excruciating decision he made, "the inner turmoil," did it give you a bigger appreciation for how difficult it is for a soldier to take up arms against his own country? While not relevant to America today, there are many countries in the world that are being torn apart by civil war.

It was an especially excruciating decision for Lee because while he believed his duty lay with his native state of Virginia, he personally opposed secession. When Lee turned down command of the main Union army, his mentor in the military told him, “You have made the greatest mistake of your life.” Lee’s wife described the act of resigning from the U.S. Army as “the severest struggle of his life.”

Perino: In present day, there are still major debates about what the Founders intended, which is something Lee wrestled with as well. What do you think Lee would think about how far we've come as a nation?  And is there anything that was learned during that time that is applicable to today's policy debates?

The debates we have today over what the Founding Fathers would do show how our understanding of the past can influence our future. 

We can take solace in knowing that our debates today are nowhere near as divisive as they were at the start of the Civil War. Back then, Unionists and secessionists both cited George Washington’s actions as precedents for their own. Lee himself took the view that the Founding Fathers would have condemned secession, though his opinion on that question changed later in life.

Perino: In the book's acknowledgements, you note that your wife, Caroline, told you to "just go write." I'm wondering, for a project like this, where do you even begin?

I once read an interview where the great American historian David McCullough said, “I try to write the kind of book that I would like to read.” That’s the goal I had in mind when I started this book. There is nothing more fun to do.

Dana Perino currently serves as co-host of FOX News Channel's "The Five" (weekdays 5-6PM/ET). She previously served as Press Secretary for President George W. Bush. She is the author of the new book "Let Me Tell You about Jasper : How My Best Friend Became America's Dog" (October 25, 2016). Ms. Perino joined the network in 2009 as a contributor. Click here for more information on Dana Perino. Follow her on Twitter@DanaPerino.