The House and Senate adopt rules that apply to their own chambers at the beginning of each new Congress. I have it on impeccable authority that a copy of the Rules the House wants to adopt on Jan. 3, 2021 indicate they want to adopt expanded committee subpoena power to go after Trump.
The Rule granting subpoena power to committees and subcommittees applies to the White House, the Office of the President, and also the Executive Office of the President and any individual currently or formerly employed in the White House, the Office of the President, or the Executive Office of the President.
These rules violate the US Constitution’s separation of powers – neither branch can encroach upon the other. In effect, this is abusive intrusion, a civil war.
Each matter would need to be definitively adjudicated assuming SCOTUS dares to pop out of its foxhole. But the Doctrine of executive privilege usually applies.
The Democrats just don’t know when to quit.