Some Republican defenders of President Trump fear White House lawyers are about to make a crucial misstep in House impeachment proceedings by not asserting executive privilege as Tim Morrison prepares to become the first current White House staffer to testify.

Morrison, brought to the White House by deposed national security adviser John Bolton, is viewed with suspicion by many Trump allies, who are expressing concern that the "superhawk" may speak without restriction and offer his opinions about work on Ukraine policy issues.

Two sources familiar with proceedings on Capitol Hill say the White House has not indicated that it will assert privilege over all or parts of Morrison’s testimony, which had been expected Friday, but which the Washington Examiner learned has been delayed to Thursday.

“It is a shit show,” said one Republican source. “There is no one at the White House coordinating this or giving guidance. ”

“It’s surprising the White House hasn’t asserted executive privilege,” said another Republican source, who noted the delay allows additional time to do so.

Morrison’s testimony could prove explosive. As senior director for Europe and Russia at the National Security Council, Morrison is one of a handful of aides who was on Trump’s July 25 call with Ukraine’s president, and one of the few who would have had access to a transcript after it was moved to a more secure system amid concerns.

Morrison is also a central figure in interactions between diplomats and the White House, including on decisions to withhold $400 million in foreign aid as Trump pushed for investigations of a Democratic server and former Vice President Joe Biden and his son Hunter, who worked at a Ukrainian energy company.

William Taylor, the top U.S. diplomat to Ukraine, testified this week that he first became aware that military aid "was conditioned on the investigations" after speaking with Morrison on Sept. 1. Morrison allegedly told him of a conversation between U.S. ambassador to the E.U. Gordon Sondland and a Ukrainian official detailing the demand.

On Sept. 7, Morrison allegedly told Taylor he had a “sinking feeling” upon learning about a conversation between Trump and Sondland in which Trump insisted that Ukraine’s president publicly announce he was opening investigations of Biden and Ukraine’s role in the 2016 election.

Morrison told Taylor that he informed Bolton and White House lawyers about the call between Trump and Sondland.

Taylor testified: "According to Mr. Morrison, President Trump told Ambassador Sondland that he was not asking for a 'quid pro quo.' But President Trump did insist that President Zelensky go to a microphone and say he is opening investigations of Biden and 2016 election interference, and that President Zelensky should want to do this himself."

Concerns about use of executive privilege, which can shield certain confidential communications among the executive branch, are being raised amid an escalating feud over strategy within the White House.

White House Counsel Pat Cipollone broadly refused to cooperate with House impeachment proceedings in an Oct. 8 letter but has since come under fire for allegedly retreating into a rhetorical cave, embracing a “bunker mentality” as Democrats investigate Trump.

Neither of the Washington Examiner’s sources for this story are administration officials. But inside the White House, acting chief of staff Mick Mulvaney and allies are attempting to push for a more forceful response to the Democratic impeachment proceedings. Mulvaney stumbled on messaging in a press conference last week, appearing to admit to a quid pro quo before backtracking.

Two White House officials told the Washington Examiner for a previous story that they believe Cipollone may have been able to prevent the entire impeachment crisis by communicating with other staff and advising Trump after concerns about the July call were raised.

Another Bolton ally, former deputy national security advisers Charlie Kupperman, who served as acting national security adviser for eight days in mid-September before departing the NSC payroll Oct. 1, is now slated to be the first former White House official to testify Monday.

The White House would not supply comment on whether it will assert executive privilege over upcoming testimony.