There's no such thing as a "political" crime: only political prosecutions.
The transfer of power is a function of our system, not the office holder.
Do you think Obama would step down if he thought he would be prosecuted after leaving office?
Or would he declare martial law and start rounding up his opponents?
Remember when the Democrats wanted to go after Bush II for ‘war crimes?’ They didn’t for just the reasons I have brought up.
Not being prosecuted for political ‘differences of opinion’ (even if they ARE criminal...) is a large part of the basis for the orderly and peaceful transfer of power in this country.
If Trump has a rejuvenated DoJ go after Hillary! after the election (as she deserves...), he sets a precedent for every subsequent election. Not a good thing.