Just because they weren't tried, doesn't mean it didn't happen. Perhaps it was just a wise move on the part of the administration to avoid trials and try to heal the nation? I understand the respect many people have for the confederate leaders and soldiers. I respect many of them and understand that it was a trying time and not easy to pick sides. Sometimes I think they made good points, other times I think the Union made good points. In the end, I think the Civil War was necessary to solve some of the prominent questions of the day. Without it, we could not have grown into the force that we became fifty years later. However, that does not mean they were not engaged in treasonous behavior.
Sorry, the treason charge doesn't stick. If you can prove otherwise, please share.