It seems like this is one of those where either way, he's going to be cast in a bad light.
(and I'm sure certain media outlets already have their talking points hashed out for either scenario)
Pardon = "She must have dirt on him, and he's letting her out so she won't expose him"
No Pardon = "He's afraid that if she gets out of prison and starts talking to reporters, she'll spill the beans"
Ideally, the right thing for them to do would be to keep the campaign promise, release any/all info they have on the matter with the only redactions being the names of victims, everything else becomes completely public.
Granted, any files/info they have will likely be considered "underwhelming" given that people had this expectation built up in their heads about there being some mythical flash drive in a safe with an excel spreadsheet sorted by name, listing all of the celebrities and politicians, and the number of sex island visits they made. (as if that's a realistic expectation of how elite criminals operate lol)