If Snowden would be free on low-cost bail while there's a real investigation into the legality of the program (review by Supreme Court seems to be the only way) I'd support postponing pardoning until after the investigation. But since the opposite will almost certainly happen (lengthy solitary confinement and no due process for Snowden, no investigation into the legality of the programs, etc.) I support an immediate pardon. Potential hero whistleblowers who risk their freedom for all of us (whether or not Snowden is one) shouldn't have to suffer so much.