[DiogenesLamp]

It was that general order, and not any order of Lincoln's, that made declaring sympathy for the Confederate cause punishable by jail, expulsion, or even death.

And the legal basis for this is what? Is there precedent for this? Has this ever happened since then? Would the courts accept these arguments now?

[DoodleDawg]

And the legal basis for this is what? Is there precedent for this? Has this ever happened since then? Would the courts accept these arguments now?

I'll take you last question because it answers the others. No, it could not happen now. An 1866 Supreme Court case, Ex Parte Milligan (71 US 2 (4 Wall.)) ruled that military tribunals, like the one Burnside established, cannot try citizens in areas where the civilian courts are in operation.