Plugs sealed his fate when he bragged about it.
& Obama
His hands are dirty in this as well..
Bidens actions and subsequent bragging are unseemly for sure, but I think this falls under the presidents clear constitutional authority to conduct foreign diplomacy. I would actually be quite surprised to find out the diplomatic corps doesnt do a great deal of arm twisting, using American $ as carrots and sanctions or other punishments as sticks.
I also dont think the Congress has authority to demand transcripts from the president regarding discussions hes held with foreign powers in the execution of the presidents constitutional duties.