Just days before he will leave the job, Acting Attorney General Matthew Whitaker spent hours Friday answering - and not answering - a flurry of questions from members of the House Judiciary Committee.
While the Justice Department did not respond to Nadler's letter by his deadline, two senior Justice Department officials said the Justice Department is preparing a "fulsome" written response to Nadler, which is expected to address the issues about executive privilege that Nadler raised.
When Whitaker seemingly tried to joke about timing with another Democratic committee member, Rep. Sheila Jackson Lee, she was having none of it. "Mr. Attorney General, we're not joking here, and your humor is not acceptable", she said. More particularly, Democrats were prepared to home in on the independence of the Justice Department and special counsel Robert Mueller from White House interference and improper political considerations.
At the hearing, Whitaker said that he had not interfered in the Mueller investigation.
Whitaker told Nadler several times that "I do not intend today to talk about my private conversations with the president", arguing that they fell under executive privilege.
Mr Whitaker, who oversees the special counsel's inquiry into alleged Trump campaign ties with Russian Federation, was grilled by lawmakers in a hearing on Friday.
The hearing concluded with Nadler calling Whitaker's testimony inconsistent "at best". "Political theater is not the goal of an oversight hearing, and I will not allow that to be the case", he added.
Nadler also told Whitaker that he would "view with considerable skepticism any effort to decline to answer on the basis that the inquiry is related to an ongoing criminal investigation". Whitaker indicated he would not appear unless Nadler withdrew the subpoena.More news: Health Officials Say 5 Cases Of Measles Confirmed In Texas
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"Congressman, I'm not a puppet to repeat what you're saying", Whitaker said.
Within minutes of the hearing, the top Republican, Rep. Doug Collins, called for a vote to adjourn, although he was quickly overruled by Democrats.
Nadler then said his time was expired and recognized Collins to begin his questioning. But in this case the issue may become moot because the Senate is likely to confirm William Barr, Trump's nominee for attorney general, next week.
Amid a heated back-and-forth, Nadler asked, "In your capacity as acting attorney general, have you ever been asked to approve any request or action to be taken by the special counsel?" Deputy Attorney General Rod Rosenstein oversaw the investigation until Whitaker was appointed after Sessions's resignation.
In a statement on Thursday night, Kerri Kupec, a Whitaker spokeswoman, said that the acting attorney general had been assured that Nadler would not issue a subpoena "on or before February 8". "If he does not show up - though I do expect he will - but if he refuses to answer questions he ought to answer, then we will have the tools we need to ensure that we may adequately meet our own responsibilities".
Democrats on the Ways and Means committee have taken the first step to obtain Mr Trump's tax returns, which he refused to publicly release during the 2016 campaign.
Swalwell: The president has called him conflicted.