Conservative commentator Dennis Prager this week may have unintentionally fueled an ongoing debate between Southern conservatives and historians over Confederate history and symbols. On his website, Prager University, the radio talk-show host and columnist released a video that aimed to debunk the argument that the Civil War was about “states' rights” to be free of federal government intervention rather than slave-holding states’ fight to continue the institution of slavery.

The five-minute video features U.S. Army Col. Ty Seidule, who teaches and runs the history department at West Point Military Academy in West Point, New York. “Slavery is the great shame of America’s history,” Seidule said in the video, released on Prager’s website Monday. “No one denies that. But it’s to America’s everlasting credit that it fought the most devastating war in its history in order to abolish slavery. As a soldier, I am proud that the United States Army, my army, defeated the Confederates.”

Seidule also mentioned that approximately 200,000 soldiers of the Union army fighting for the North against the South were former slaves who ultimately freed 4 million slaves who were still in bondage. Slavery, “by a wide margin,” was the Confederacy's primary reason for fighting the Civil War, he said.

The Prager University video was released at a time of tense national debate about Confederate symbols and history. South Carolina lawmakers voted last month to remove the rebel battle flag that flew over the statehouse grounds, following a hate-fueled mass shooting at a historically black church in Charleston whose founders fought to end slavery. Other Southern states have discussed what to do with monuments, government buildings and street signs dedicated to Confederate figures.

In the Prager video, Seidule pointed out that Alexander Stephens, the Confederacy’s vice president, had famously defended the practice of slavery in his “Cornerstone Speech” of 1861. Stephens argued that it is a “great truth that the Negro is not equal to the white man,” Seidule said. “This raises an obvious question: the states’ rights to what? Wasn’t it to maintain and spread slavery?”