As a result of Trump publicly admitting the things he is being charged with, one would think that an investigation would not be necessary. They could go straight to the impeachment itself, not an inquiry or investigation. He can’t continue to say that he was just kidding either, that one is getting old. Nor can he say that he was ignorant of the law. Anyone else would be told that ignorance of the law is no excuse. It is a fact that he publicly confessed to the things he was accused of doing!
Trump and his ilk can’t negotiate a quid amateur quo, let alone a pro one.