Regarding your comment about how the entire ruling centers on this one point, would this mean all the US would have to do to get it overturned is pinky promise they won't throw Assange in solitary? What if they then put him in solitary anyway?
Nothing, but now you've potentially damaged diplomatic relations with an ally. Countries generally (!) try to keep their promises to each other, or they won't be considered reliable in the future. Just like individuals.
