Regardless, if this is how the pardon comes about, I happily support it even if it’s not ideal.
That would be only one of the charges. And a reasonable Snowden defence would be to recite the oath he swore to the Constitution. If this were the only charge, I don't rule out a fair trial.
But the second charge would be revealing NSA programs operating outside inside USA borders. This was the reason Obama didn't want to write a pardon, and the reason Pompeo sides with executing Snowden. The accusation that Snowden was working for a foreign intelligence agency hinges on two questions: why did he reveal those overseas programs, and how did he get onto (or know to get onto) Aeroflot without a passport.
This is why he can be simultaneously a patriot and traitor. Trump (or his predecessor) could have written a pardon the first charge and deliberately left out the second. Whether Snowden would want to take his chances with a trial on the second charge would be a tough choice.
That we can't just mechanically apply the law like the axioms of mathematics is part of the very reason that we have judges, juries, and the adversarial system, to allow for some measure of human judgement in the process.
A jury can even be sympathetic... and still convict him.
I hear folks talk about a fair trial but he's already admitted to crimes... so is the "fairness" only determined by a highly unlikely outcome, I'm not sure that's about fairness.
It's not like a legal argument about what you knew or when and what the law says about your responsibility / actions.
A jury ignoring admissions of crimes is pretty rare and a roll of the dice.
I get why people would want that to happen, but expecting that random chance of an outcome and using it to measure fairness, I dunno, they're likely to be disappointed.
It boggles the mind that some can attempt to justify the egregious actions of the US intelligence community while supporting the railroading of a whistleblower. Perhaps the intelligence community could be more responsible and compliant with statute, negating the need for whistleblowers to reveal their illegal activities.