[central_va]

Now strictly speaking, Lee and the rebels were guilty of treason.

Maybe not.

[DoodleDawg]

Secession wasn’t treason. Armed rebellion was, and they were certainly guilty of that.

[BroJoeK]

central_va quoting Salmon Chase:

Here are the problems:

1. Chase was a Democrat then running for the Democrat nomination for President.
   
2. Naturally Northern Democrats did not want to hang their Southern Democrat allies, rather they wanted Southern votes!
   
3. Like Democrats of the time & later, Chase here confuses the question by claiming "secession is not rebellion".
   No, but rebellion is rebellion and waging war against the United States is defined as treason by the Constitution.
   
4. Oh, but they weren't citizens so it can't be treason, they say.
   Maybe, but Confederates put Southern Unionists in jail or forced them to fight & die for the Confederate cause, how just was that?

Bottom line: Lincoln, Grant, Chase & others were correct to treat former Confederates as leniently as possible, especially as they ratified the 13th, 14th & 15th amendments.
But they left us much to debate even 150+ years later!

[jmacusa]

Secession is one thing General. Armed rebellion against a duly elected government is another.