If you are going to champion someone you might at least get his name right: Clement Laird Valandigham and not Clarence VanLandingham.
Regardless, Valandigham specifically set out to challenge Ambrose Burnside's General Order making it illegal to speak in support of the Confederate cause. Now we can debate all day about the legality of the order, and probably agree that it was illegal, but Valandigham set out to become a martyr and Lincoln actually denied him the opportunity by immediately commuting his sentence and expelling him to the Confederacy. The Davis government was so thrilled at his support that they kept him under guard until such time as they could ship him to Canada.
Except, he carefully avoided speaking in support of the Confederacy, merely in opposition to Mr. lincoln’s policy (in order to push the envelope on the order.)
Further, the Legislative Branch would not have authority to outlaw speech, let alone a general acting on his own authority.