The Senate is set to return on Friday from a two-week holiday recess with negotiations over the impeachment trial at an impasse.

Democrats want the trial to include Ukraine-related documents and four witnesses: Blair, Mulvaney, Bolton and Duffey. Schumer has also specified that Democrats want one resolution, passed at the outset of the trial, that would outline both procedure and an agreement on specific witnesses.

“This new evidence also raises questions that can only be answered by having the key Trump administration officials—Mick Mulvaney, John Bolton, Michael Duffey and Robert Blair—testify under oath in a Senate trial," Schumer said Thursday.He added that Duffey's email saying there was a "'clear direction from POTUS to continue to hold’ only further implicates President Trump and underscores the need for the Senate to subpoena the witnesses and documents we’ve requested at the onset of a trial. The American people deserve a fair trial that gets to the truth, not a rigged process that enables a cover-up.”