I know the theory floating around about Mitch the Bitch telling him he would be impeached if he pardoned Assange, and many have speculated his family was also threatened.
However, I still count the President too smart to believe the deep state would honor their word. In reality, it doesn't matter what he does because the deep state is going to go after him no matter what.
So what gives? Assange will now most likely die in prison, and it looks like it would have been incredibly easy for the President to pardon him.
Why leave Snowden and Assange to face trial when they committed no crimes?
I have heard that The Turtle was threatening to scrape up enough votes to convict him in the upcoming unconstitutional impeachment trial if he did. I cannot confirm though