That one is a no brainer. Chump decided to send a message that as first Emir of these disunited sates, he and his buds can do whatever they want - or what he wants and he has the power of all kings and dictators to do whatever he wants. He is above teh law. He is such a winner that maybe he thinks he is a god.
Approve or disapprove of Sheriff Joe, he was convicted in a court of law and has the right to appeal. At this stage he has not even been sentenced yet. So for El Preidente to step in now and pardon him seems to be completely inappropriate and is a combination of political stunt and to send a warning that he and anyone he likes is above the law. Sad. Very sad.
In a few short months the US has gone from being seen by many as a flawed but generally OK country that leads from the front, to being seen as a petty, failing dictatorship.
There have been a few books and articles written about fallen empires and how the end for the US as a major power is inevitable. I doubt any of those authors saw it coming so fast. Sessions and Trump now want to make it into a military state and want to give police forces even more military equipment so they can rigidly enforce the law on anyone that gets out of line.
Not a good time to be not rich or not white. Of course over time as the economy falters and civil unrest grows, those billionaire buddies he is trying to impress will be less happy too, so I guess in the end everyone loses out to some degree. That sounds more like a Bannon plan.