The House Judiciary Committee Chairman on Tuesday issued a subpoena for longtime Trump press aide Hope Hicks, in the latest escalation of the battle for documents and testimony.

The Democratic-led panel issued the subpoena hours after former White House counsel Don McGahn adhered to a White House directive and defied a subpoena to appear before the committee.

Hicks, 30, joined Trump's campaign from the Trump Organization, than followed her boss to the White House, where she became communications director, putting her near the center of key decision points. Upon leaving, she landed a job at Fox Corporation, parent company to Trump's preferred network, Fox News.

The House Judiciary has subpoenaed former White House Communications Director Hope Hicks seeking documents and testimony

As part of the initial skeleton crew of Trump's campaign effort, she is privy to an array of business and political information, and interacted with key players including McGahn, longtime Trump lawyer Michael Cohen, and top campaign staff.

The subpoenas seeks information as well as a June appearance from her.

Hicks was among a group of 81 individuals and entities Nadler sought information from earlier this year as part of a sweeping investigation.

A document request sought information about the Comey firing, former national security director Mike Flynn, the recusal of former attorney general Jeff Sessions, a Trump tower project in Moscow, the response to the infamous Trump Tower meeting with Russians, and other topics. Initial indications were that Hicks was complying.

The panel also subpoenaed Annie Donaldson, who served as McGahn's chief of staff.

Her notes provided memorable fodder for Special Counsel Mueller's investigators.

She wrote of a 2017 internal meeting: 'POTUS in panic/chaos ... Need binders to put in front of POTUS. (1) All things related to Russia.'

And after Trump fired FBI Director James Comey, Donaldson wrote: 'Is this the beginning of the end?'

The committee last month voted to authorize subpoenas for Hicks, McGahn, former chief White House strategist Steve Bannon, former chief of staff Reince Priebus, and Donaldson.

Rep. Jerold Nadler said Tuesday that Donald Trump's conduct detailed in the Mueller report 'constitutes a crime' – and would be prosecuted were Trump not president.

Hicks, 30, joined Trump's campaign from the Trump Organization, than followed her boss to the White House, where she became communications director

Nadler, who has considerable influence over whether House Democrats go down the path of impeachment, made the stark statement Tuesday at a hearing where former White House counsel Don McGahn adhered to a White House directive and defied a subpoena to appear before Nadler's committee.

With no witness present, Nadler read aloud passages from the Mueller report – including passages describing when Trump told McGahn to contact deputy attorney general Rod Rosenstein and tell him to push out Mueller, and then later draft a memo stating that Trump never told him to fire Mueller.

'I believe that each of these incidents documented in detail in the Mueller report constitutes a crime,' Nadler said, of the report's 10 instances of potential obstruction.

Former White House counsel Don McGahn defied a House Judiciary Committee subpoena on Tuesday. Chairman Jerold Nadler vowed: 'We will not allow the president to prevent the American people from hearing from this witness'

'But for the Department of Justice's policy of refusing to indict any sitting president I believe the president would have been indicted and charged with these crimes,' he continued. Then he cited a letter from 900 former federal prosecutors who signed a letter saying Trump would be charged if it weren't for internal guidelines against a sitting president being charged.

'I believe that the president's conduct since the report was released with respect to Mr. McGahn's testimony and other information we have sought have sought has carried this pattern of obstruction and cover-up well beyond the four corners of the Mueller report,' Nadler said.

'The president has declared out loud his intention to cover up this misconduct. He told Mr. McGahn to commit crimes on his behalf. He told Mr. McGahn to lie about it,' Nadler added.

President Trump hit back on Twitter, but not until late Tuesday afternoon.

'So even though I didn’t have to do it with Presidential Privilege, I allowed everyone to testify, including White House Counsel Don McGahn (for over 30 hours), to Robert Mueller and the 18 Angry Trump-Hating Democrats, and they arrived ...at a conclusion of NO COLLUSION and NO OBSTRUCTION!' Trump wrote.

'The Dems were unhappy with the outcome of the $40M Mueller Report, so now they want a do-over.,' Trump wrote.

Nadler's searing statement came as McGahn defied a House Judiciary Committee subpoena Tuesday – failing to show up for a hearing after the White House directed him not to appear and stated his immunity from subpoena.

Nadler blasted President Trump for efforts to 'intimidate' a witness, saying it was 'not remotely acceptable.'

'The witness must show up,' Nadler intoned. 'Our subpoenas are not optional.'

'If he does not immediately correct his mistake, this committee will have no choice but to enforce the subpoena against him,' Nadler said of McGahn at the start of the hearing, which continued without the witness present.

Nadler said the panel would hear from McGahn 'even if we have to go to court to secure it.'

'We will not allow the president to prevent the American people from hearing from this witness,' he said.

'We will not allow the president to block congressional subpoenas, putting himself and his allies above the law,' Nadler added. 'We will hold this president accountable, one way or the other.'

Ranking member Rep. Doug Collins of Georgia resonded, after Nadler read passages from the Mueller report based on McGahn's testimony – including McGahn's efforts to prevent Trump from pushing out Mueller.

VACANT: A name placard is displayed for former White House Counsel Don McGahn, who failed to appear despite a subpoena

McGahn features prominently in the Mueller report, which describes phone calls he received at home from Trump. McGahn says Trump told him to contact the deputy attorney general and have him tell Mueller he couldn't be special counsel

Nadler accused President Trump of intimidating McGahn from appearing

Ranking Member of the House Judiciary Committee, accused Democrats of not engaging in the 'accommodation process' and 'rejecting olive branches from the administration'

Collins says Nadler left out that: 'There was no collusion. There was no obstruction charges. There's nothing here. After two years of doing this.'

He accused Nadler of seeking 'drama' and headlines, rather than information.

'I cannot emphasize this enough. The track record demonstrates he does not actually want information. He wants the fight, but he does not want the truth.'

He pointed to an incident when Attorney General Bill Barr refused to comply with a subpoena to appear, after Nadler insisted he be question by committee counsel about the Mueller report. The Democratic-run panel voted to hold Barr in contempt.

Trump has said he is fighting 'all of the subpoenas.'

On the committee's obstruction of justice inquiry, Collins said: 'That investigation was already done. Robert Mueller spent two years running it and then closed it,' he said.

'You know the one thing that we seem to avoid is Mr. Mueller himself, the one who wrote it,' said Collins. He claimed Democrats 'don't want to talk to the author.'

Collins accused Democrats of not engaging in the 'accommodation process' and 'rejecting olive branches from the administration.'

Mueller examined ten cases of potential obstruction, but made no determination. His report referenced the role of Congress, and Barr made his own determination not to prosecute two days after Mueller turned in his report.

After Nadler and Collins spoke, the committee quickly voted to adjourn – avoiding a prolonged hearing that might have lead to new talk of impeachment.

The subpoena fight came as House Speaker Nancy Pelosi is fending off an intensified push from fellow Democrats and Judiciary Committee members who want to push ahead with an impeachment inquiry of President Trump.

The push comes after the White House has denied a series of requests for information – including a Judiciary Committee subpoena of the un-redacted Mueller report and Trump's tax return information. It also follows Attorney General William Barr's refusal to attend a Judiciary Committee hearing on the Mueller report.

The White House directed McGahn not to appear, citing Justice Department guidance that requiring a presidential advisor to appear is akin to forcing the president himself to appear, and therefore a violation of his own constitutional powers. It claimed his former role provides him 'absolute immunity' from being required to testify.

'The Department has long taken the position –across administrations of both political parties –that 'the President and his immediate advisers are absolutely immune from testimonial compulsion by a Congressional committee,' according to a letter from current White House counsel Pat Cippollone.

McGahn rejoined his law firm Jones Day after leaving the White House. This gives the White House an additional point of leverage. The firm represents the Trump campaign.

The Republican National Committee's top expense last month was $2 million paid to McGahn's firm. The Washington Post reported that were McGahn to testify, Trump has 'mused about instructing Republicans to cease dealing with the firm, which is deeply intertwined in Washington with the GOP'

He rejoined his old firm in March, and now heads its government regulation practice.

The issue came to head at a closed-door leadership meeting in Pelosi's office Monday.

Lawmakers including Rep. Jamie Raskin, David Cicilline of Rhode Island, and Joe Neguse of Colorado are pushing to move ahead on an impeachment inquiry now.

'Those of who serve on the house Judiciary Committee have been exposed right up front and close to Presidential obstruction of justice and high crimes and misdemeanors for a long time now,' Raskin told CNN Tuesday morning.

'And we are at a certain point in our educational process … that a lot of us think the logic may be inescapable – not for impeaching or not impeaching – but for launching an investigation into high crimes and misdemeanors so we can figure out what to do. The Constitution gives us a pathway through this crisis,' he said.

Cicilline tweeted Monday: 'If Don McGahn does not testify tomorrow, it will be time to begin an impeachment inquiry of @realDonaldTrump.'

During the hearing Tuesday, he tweeted that the witness 'is not present. I've made clear what this means for me.'

Pelosi, meanwhile, has cautioned in public and in private on the need to allow the investigatory process put in place to proceed – even amid White House defiance.

She was able to point to a Monday court ruling where a federal judge ruled that an accounting firm must comply with a subpoena for Trump financial information.

'You want to tell Elijah Cummings to go home?' she told members, bringing up a House Oversight Committee investigation.

The split came hours before the Judiciary Committee was to meet to hear testimony from former White House counsel Don McGahn, who didn't show up, after the White House determined he should not as a former advisor to the president.