Also on Tuesday, George Kent, the State Department official in charge of Ukraine policy, was the latest witness to be questioned. Fiona Hill, Trump’s former Russia adviser, sat down for more than 10 hours on Monday.

Watching this, officials are growing frustrated because they are mainly being forced to learn about what these officials divulged from news reporters. There is no White House counsel present in the room and officials are not given transcripts or readouts after they leave, one person told CNN.

The White House sent an eight-page letter declaring war on the inquiry by deeming it unconstitutional — but officials have been unable so far to prevent officials from complying with requests and subpoenas.