One thing that is clear from the hearings is that the Democrats are trying to make the case that using outside channels for diplomacy is unusual or wrong. Read a very good piece this morning that puts that canard to rest. You may not like Rudy or Perry or Sondland and their work in Ukraine, but that is clearly the President's perogative and has been used often. From the article:
What follows below is a description of the U.S. president’s authority when it comes to who he can appoint to conduct diplomacy.
It was written in 1960 by Henry Wriston, President Emeritus of Brown University; Chairman of the Secretary of State’s Public Committee on Personnel, 1954-56; President of the American Assembly, Columbia University; author of “Strategy of Peace,” “Diplomacy in a Democracy” and other works.
Wriston’s description makes clear that President Trump’s use of Giuliani, Volker, Sondland and anybody else he pleases is clearly within his authority– not “irregular” or sinister “shadow diplomacy.”
Quids pro quo and using personal representatives to conduct diplomacy are not controversial.