You're making it sound as though the rule of law is something that is actually respected in the US. It isn't. The facts don't matter. If (although it now seem more like a matter of when) Assange leaves the embassy, he can expect to be arrested and extradited to the US.
You are also confusing a regular prison and a military prison. Two different species. And that's making the assumption that he might not end up in one of Gina's "special" prisons
No I had a opinion that our government knows they will pay the price if they try and imprison Assange, it won't be taken lightly by the American people.
They can't even bring him here unless they can prove to a judge that there is enough evidence to prove he stole the materials published and/or that there is enough evidence to warrant bringing him here for questioning as to who did. The latter being more probable.
Even if they could come up with something substantial it would fall under the federal laws, which means the federal prison system, which for the most part are a lot better than state operated prisons.