There's nothing to stop a president from pardoning himself but after this affair is over Trump will no longer be president and so he will no longer be in a position to pardon himself.
The question isn't about whether this is the case
This seems obvious to me, and I'm sure to everyone else as well
The question I'm asking is why isn't this obvious to Trump?
Why on Earth would Trump think he'd be in a position to pardon himself?
Nixon was pardoned after he quit but before charges were filed, so was essentially pardoned in advance of any legal case and possible conviction. Gerald Ford did this for him, and it basically terminated the investigation.
It's easy to think, then, that Trump (who doesn't care for tradition and has no sense of shame) may be investigating whether a persident can pre-emptively pardon themselves of unspecified charges.
The legal commentators that I follow seem to think that if he tried to do this it'll end up on the SCOTUS's plate, and they'd have to make a ruling as to whether or not it was constitutional.
EDIT: If it's judged to be constitutional then that could be trouble. It would essentially gives the president a blank cheque to do what the hell they want to, disregarding legality, as they can get themselves out of jail for free for Federal crimes. Still, state-level prosecutions would still be possible but it'd be a horrible headache.
