In addition, the Sons of Confederate Veterans and some of its local chapters are preparing various television commercials that they hope to show next year. “All we wanted was to be left alone to govern ourselves,” says one ad from the group’s Georgia Division.

Image Left, taking in a piece of history at the Gettysburg National Military Park. Right, Jefferson Davis, the leader of the Confederacy. Credit... Left, Tim Sloan/Agence France-Presse--Getty Images; Mathew Brady/The National Archives, via Associated Press

That some — even now — are honoring secession, with barely a nod to the role of slavery, underscores how divisive a topic the war remains, with Americans continuing to debate its causes, its meaning and its legacy.

“We in the South, who have been kicked around for an awfully long time and are accused of being racist, we would just like the truth to be known,” said Michael Givens, commander-in-chief of the Sons, explaining the reason for the television ads. While there were many causes of the war, he said, “our people were only fighting to protect themselves from an invasion and for their independence.”

Not everyone is on board with this program, of course. The N.A.A.C.P., for one, plans to protest some of these events, saying that celebrating secession is tantamount to celebrating slavery.

“I can only imagine what kind of celebration they would have if they had won,” said Lonnie Randolph, president of the South Carolina N.A.A.C.P.