Four White House officials on Monday did not comply with congressional subpoenas for their testimony, prompting the top Democrat on the House Intelligence Committee to warn that their refusal to appear would further inform Democrats' inquiry and a possible article of impeachment on obstruction of Congress.
"Today we have four additional subpoenas to add to the list of initial charge involving the president of the United States and his obstruction of our constitutional duties," House Intelligence Committee Chairman Adam Schiff, D-Calif., said to reporters as the committees released the first of more than a dozen depositions transcripts.
While several witnesses have sought court actions to adjudicate their subpoenas, Schiff signaled that Democrats wouldn't delay their investigations to wrangle with the administration and potential witnesses in court.
"We're not going to delay our work," he said. "That would merely allow these witnesses and the White House to succeed with their goal which is to delay, deny, obstruct."
At the start of a week packed with scheduled closed-door depositions, Democrats hoped to hear from John Eisenberg, deputy counsel to the president for national security affairs; Michael Ellis, senior associate counsel to the president; Robert Blair, a top aide to the acting chief of staff; and Brian McCormack, an official with the Office of Management and Budget who previously worked for Energy Secretary Rick Perry.
(MORE: Obey White House or subpoena? Witness in impeachment probe asks judge to decide)Paul Butler, a lawyer for Ellis, told ABC News his client has been instructed not to appear on Capitol Hill Monday, adding that the administration considers the congressional subpoena "invalid" because Democrats have not allowed administration counsel to appear for depositions, among other concerns.
The White House has pushed back on permitting current and former officials to comply with requests and subpoenas from Congress in part because White House lawyers have not been permitted inside the closed-door interviews.
"Mr. Ellis remains respectful of the lawful powers of the United States House of Representatives and, as a lawyer and member of the bar, remains willing to comply with a subpoena issued under lawfully valid terms and conditions, or any other resolution of this dispute between the Executive Branch and the Congress," Butler wrote in a letter to the committees.
John Eisenberg, the top White House lawyer at the National Security Council, also did not appear on Capitol Hill Monday, citing a similar rationale, according to a letter sent to lawmakers by his attorney, William Burck.
Current National Security Council adviser Lt. Col. Alexander Vindman and former National Security Council aide Tim Morrison did comply with congressional requests last week, however, they are career officials and not political appointees like the four individuals slated for Monday.
An attorney for Blair told the committees that his client was not planning to attend Monday's hearing.
Blair's position is similar to that of former deputy national security adviser Dr. Charles Kupperman. Kupperman took things a step further last week filing a civil lawsuit to seek input from a federal judge on whom to comply with -- his former employers at the White House who requested he not comply, or lawmakers on Capitol Hill that have subpoenaed him for testimony.
(MORE: Rep. Scalise raises concerns about politically motivated impeachments)His lawyer, Charles Cooper, argued last week in D.C. District Court that his client is in a "catch-22." That case is slated for oral arguments in December.
Cooper is also representing Kupperman's former boss -- ex-national security adviser John Bolton -- who was invited by the House for a deposition later this week. Bolton's attorney said he will not comply with that request, however, if the committee wants to subpoena him they can.
It's unlikely Bolton would immediately comply with that subpoena, according to sources familiar with his thinking.
Separately, an Office of Management and Budget official said that not only will McCormack not show on Monday, but Michael Duffey, OMB's associate director for national security programs, and acting OMB Director Russell Vought will not appear for scheduled closed-door depositions on Tuesday and Wednesday, respectively.