Then you are naive, at best. Even if he came back to the states today, there is no possible way for him to get a fair trial. It would be a huge miracle for such a trial to even be public, given our government.
Consider that it took one person eight years to get taken off the no-fly list after being put on for what is reportedly a government mistake. Part of the reason (if not the entire reason) for that was the continued insistence by the Justice Department that they couldn't reveal why she was on the list, even just to her own attorneys, because it was a state secret:
Holder and Clapper argue that U.S. national security could be seriously or significantly harmed if Ibrahim or her lawyers are provided with classified information about whether she was the subject of an intelligence or terrorism investigation or about the standards for inclusion in a database called the Terrorist Identities Datamart Environment (TIDE) could harm national security.
This is how our government reacts for a single individual who has been unable to use air travel because of the mistake of a lone public worker.
While he did technically break many laws, it was justifiable because of the sincere good it did in revealing just how unconstitutional our government acts, which is the first step necessary to making it stop. In order to prove that it was justified, he would have to present evidence of the wrong-doing of the government. Do you honestly believe he wouldn't be completely stonewalled and railroaded by the Justice Department, Congress, and whoever was the President? Even if the documents are now in the public eye, they can still be withheld from trial; nevermind the mountain he would have to claim to extricate extra documentation from the NSA proving how much shit they do.
The only way for Snowden to come back with any hint of safety is a Presidential Pardon; I'll know our nation has finally grown up and stopped being scared of the invisible monster under its bed once that happens, if it ever does.