Joe said he wouldn't pardon Hunter, and I expect him to live up to that promise.
If he had not made that promise, the fact that the prosecution was highly political would be a reasonable argument to pardon him.
I know nothing about the judge. If the judge is reasonable, and can be expected to impose sentences similar to others convicted of similar offenses, then Hunter shouldn't be hit too hard. But if there's any reason to think that the judge wants to build his career by being a hanging judge on this case, Joe should renege on his promise.