If the USA really wanted to go down this scary path, then wouldn't Bradley Manning have been executed by now? His leak most likely was much more damaging to the US than Snowden, and he is on trial via a military tribunal which has a much greater conviction rate than a civilian court. Manning isn't even on trial for any charges that carry the death penalty.
Bradley Manning's treatment to date is essentially torture. The message that the US is trying to send is 'If you cross us, we'll torture you until the end of your days.'
Death is an easy out. Become a martyr? Not so bad. Live for the rest of your life, naked, in solitary confinement? I'd rather be dead than lose my grip on sanity in those kinds of conditions.
