The Confederates traitors? The author of the article needs to read some history and I don’t mean modern rehashing, or some program on PBS, but the original words of people involved.
Sure, many Northerners considered the Confederates traitors, but then why didn’t they follow through, and hang anybody on these grounds? Probably because they would have lost the cases in court.
You also find in history that before the War of 1812, New England almost left the Union. A couple of generations later, they were calling others traitors for trying (more successfully) to do the same thing!
There is a book on this subject: Albert Taylor Bledsoe, Was Davis a Traitor; or Was Secession a Constitutional Right Prior to the War of 1861? Published in 1907. Available free on line at Google Books:
Correction: the title if the book is “Is Davis a Traitor...”