If he'd stood up for US citizens rather than US enemies he could have remained in the US and fought his corner in the courts and the press.
He would be convicted, he clearly violated the law. An unjust law perhaps, but a law nonetheless. He swore not to give Top Secret to anyone without a security clearance and he obviously did.
It's possible that one of the room service delivery people was a Chinese agent and made Snowden an offer he couldn't refuse: "USA has issued an arrest warrant....we may have to arrest you...but...what do you have for us? "