As many cities debate what to do about monuments to Confederate leaders and soldiers, defenders of such monuments commonly claim they “have nothing to do with hate or racism but everything to do with our history and heritage,” as a Tampa resident proclaimed Wednesday to his county commissioners before they voted to keep a nearby monument.

But not every aspect of that heritage and history is well known. And residents of the American South have been debating their very heritage and the historic ideas for which the Confederacy stood even before those 11 states seceded in 1861. There is no better proof of that divide than a book that was published 160 years ago Monday, on June 26, 1857: The Impending Crisis of the South: How to Meet It by Hinton Rowan Helper. The book and the author have long been forgotten in popular memory. But Helper’s Impending Crisis of the South is the only book other than Harriet Beecher’s Stowe’s Uncle Tom’s Cabin that historians have kept in their bag of causes of the Civil War.

Better than any book of the tumultuous 1850s, Helper’s book circulated the ten-year-old rope that slaveholders feared could bind together non-slaveholding white people above and below the Mason-Dixon line. The rope had a name: free (white) soil.

“Freesoilers and abolitionists are the only true friends of the South; slaveholders and slave-breeders are downright enemies of their own section,” Helper unabashedly declared in The Impending Crisis. “Anti-slavery men are working for the Union and for the good of the whole world; proslavery men are working for the disunion of the States, and for the good of nothing except themselves.”

Helper was a native of North Carolina. At 9 months old in 1830, his minor slave-holding father died, and failed to bequeath any riches. He learned to write at a nearby academy, but flunked as storekeeper. He migrated to New York City in search of riches in 1850. Jobs eluded him, so he rushed to California for his fortune. ...