Parnas, who is facing federal campaign finance charges in Manhattan, has publicly turned on Trump and his allies. He petitioned the court to allow him to release the information to Congress and has offered to testify in the impeachment trial and to cooperate with prosecutors in New York investigating Giuliani. And he undertook a media tour of sorts this week in which he claimed that the president “knew exactly everything that was going on that Rudy Giuliani was doing in Ukraine.”