RE: I thought quid pro quo was the essence of foreign relations.
It is, but NOT if an individual or his family is PERSONALLY the benefit of the quid pro quo.
You are supposed to be serving the interest of your country, not yourself.
It's Trump's JOB.
And it was his top priority to find out whether the Biden family was influenced by Ukraine, while there is an ongoing election cycle.
You would think VP Biden was aware of this caveat.