Indicting/jailing a sitting president would interfere with his/her doing the job. So it is not done until AFTER the sitter gets up and moves on.
HOWEVER that gives license to the criminal to continue criminallying since nothing he does can be punished. Now no criminal prez is going to do anything a country needs to have done. His/her time in the chair means nothing but more crimes against the people.
So once again we are operating on an illogical premise. People defend it mightily. Makes no sense. We should CUT OUR LOSSES as soon as possible. Wouldn't that be what intelligent people would do? I'm jes sayin'...