The Confederate States seceded from the United States over slavery. But the “lost cause” myth—the idea that the Civil War was not about slavery but about northern aggression—still has a hold on countless Americans.

The historian Ty Seidule doesn’t believe that anymore, though he only came to the realization well into his career as an Army officer and a history professor. His book Robert E. Lee and Me deconstructs the legacy of the top Confederate general and unpacks the enduring “lost cause” ideology.

On this week’s episode of The Experiment, the correspondent Tracie Hunte talked with Seidule about why unlearning the mythology surrounding Lee took him so long, and the host, Julia Longoria, considers what it might take for other white Americans to do the same.

Be part of The Experiment. Use the hashtag #TheExperimentPodcast, or write to us at [email protected].

This episode was produced by Tracie Hunte and Matt Collette, with editing by Katherine Wells, Julia Longoria, and Alvin Melathe. Fact-check by William Brennan. Sound design by David Herman. Special thanks to Adam Serwer, Vann R. Newkirk II, Veralyn Williams, and Jenisha Watts.

Music by Keyboard (“Shingles,” “Contractions”), Parish Council (“St. Peter Port/Wiltshire/Cooking Leeks,” “Socks Before Trousers,” “Leaving the TV on at Night”), Ob (“Waif”), and infinite bisous (“Brain”); provided by Tasty Morsels. Additional audio from CBS, Military Videos, the Associated Press, Congressman Steve Womack, the U.S. Naval Academy, CBSN, and Senator Lindsey Graham.