"As for the hearing scheduled for December 4, we cannot fairly be expected to participate in a hearing while the witnesses are yet to be named and while it remains unclear whether the Judiciary Committee will afford the President a fair process through additional hearings. More importantly, an invitation to an academic discussion with law professors does not begin to provide the President with any semblance of a fair process. Accordingly, under the current circumstances, we do not intend to participate in your Wednesday hearing," White House counsel Pat Cipollone wrote in a Sunday evening letter to Chairman Jerry Nadler.

The absence of White House participation follows weeks of vocal protests from the president and Republicans in Congress, who have accused Democrats of blocking their due process rights.