Best thing would be to send him somewhere where he can't make any trouble. We still have a base in Antarctica, right?
You know that a treason charge or something of that sort is just what the anti-war crowd is waiting for. Don't give them the attention they want. Like at the capital hill steps a couple months ago, where they vandalized the site. They wanted to be confronted and hoped to draw violence. Wanted to make people think they were Gandhi or something. Letting them make fools of themselves and not arresting them was the right thing to do. The only kind of news they'll make then is negative news.
Do you know what the history of soldiers who do what this guy is doing? During WWII or Korea? Usually they sent them to the front lines, right? Did they ever execute any of them?