Bill Barr et al have argued that the laws changed after Nixon because he was going to destroy documents.
These documents supposedly belong to the people.
But they pretend that only one copy exists or can exist.
So, they are just fighting to keep these documents from Trump.
It’s either because they contain incriminating evidence against them, or it is merely entrapment.
Read a while back that they are after only one particular ‘notebook’ that they did not find at Mar-A-Lago.
This notebook supposedly has what you referred to as “incriminating evidence against them” and they are desperate to get it back...................