If Snowden ever does get a trial, they won't prosecute him for anything he leaked to avoid his justifiable defense. He admitted transporting classified docs to China that were never released because the information did not involve illegal surveillance. They can put him away for life just for admitting to mishandling top secret data regardless if he released it or not. Pretty sure there are clear rules on storing that data and none include taking it on laptops to China encrypted by software likely not approved. He can never come back because of talking too much to the media, all that can be used against him

Watch this http://youtu.be/6wXkI4t7nuc then imagine you are a federal prosecutor tasked with prosecuting Snowden. Go through all his interviews and find crimes he admitted to not related to the 200k docs he sent to journalists to prevent any defense. Bonus points find inconsistent statements you can manipulate to claim he is a liar to further wash away any defense. Automated tools to grab indiscriminate secret docs, illegal transportation, tons of potential crimes there based on his own admissions alone.