Washington (CNN) Democrats aimed a fresh dagger at Donald Trump's inner circle by subpoenaing documents from his lawyer Rudy Giuliani , as the President struggled to parry an aggressive impeachment gambit on a day of rapid developments.

The President seems to be reeling, waiting for the next blow to fall, defended only by his increasingly unhinged tirades, his tweets quoting supporters on cable news and confrontational and conspiracy-laden appearances by aides on TV.

The President's unaccustomed struggle to control the narrative and to get his opponents to respond to his moves bodes ill for any hopes he has of avoiding a full House impeachment vote.

There is no sign of the organized, disciplined political and legal strategy that for instance helped Bill Clinton emerge from his impeachment trial as a viable President.

For days now, Trump has been unable to slow the momentum of Democrats as they investigate whether he abused his power by trying to pressure Ukraine to dig for dirt on potential 2020 foe Joe Biden and his son Hunter.

CNN reported Monday that Trump loyalists had warned him that he would almost certainly be impeached and that some doubted whether he really understood the magnitude of his plight.

Digging himself in deeper, Trump warned Monday he was trying to find out the name of the official who blew the whistle on his call and dealings with Ukrainian President Volodymyr Zelensky. Trump's comment could be a potential violation of laws meant to protect truth tellers and could play into any eventual charges by Democrats that he is seeking to obstruct their investigation.

The whistleblower's lawyers have already raised concern for their client's safety, as Democrats try to persuade the unnamed official to tell the story that sparked their complaint on Capitol Hill.

In tweets and remarks that seemed increasingly panic-stricken, Trump fulminated at Rep. Adam Schiff, the House Intelligence chairman who has been made the initial face of the impeachment inquiry by House Speaker Nancy Pelosi.

He seized on a supporter's comment on Fox News that he feared a "Civil-War like" fracture in the country and called for Schiff to be investigated for treason. He also took aim at his accuser.

"The whistleblower reported a totally different statement," Trump said at the White House. "I made a call. The call was perfect. When the whistleblower reported it, he made it sound terrible."

Acting Director of National Intelligence Joseph Maguire, however, told lawmakers last week that the whistleblower's complaint was credible and that he or she acted lawfully and in good faith.

On Tuesday morning, the administration made its most significant attempt yet to stall the momentum of the Democratic impeachment effort. Secretary of State Mike Pompeo said in a letter to House Democratic chairmen that it was not feasible for State Department officials to give depositions on Capitol Hill this week. In a tweet, Pompeo also accused Democrats of attempting to "intimidate, bully, & treat improperly the distinguished professionals" from the State Department.

While there are so far few signs of a collapse in support among GOP lawmakers for Trump, shifting poll numbers so far suggest the President and not the Democrats face the biggest risks in the impeachment showdown.

A new CNN/SSRS poll shows that Americans are roughly split on whether the President should be impeached. But in a worrying sign for Trump, support for impeachment and removal rose 11 points to 46% among independents.

Trump's control over the Republican Party -- an insurance blanket in case of a Senate impeachment trial -- has been rooted in high levels of support among conservative base voters.

The President reflected that strength by tweeting out an electoral map Tuesday overlaid with the words "Try to impeach this." The graphic was overwhelmingly red given the dominance of Republicans in rural territory outside major cities.

Support among Republican voters for impeachment and removal edged up to 14% in the CNN poll. But 80% of Republican respondents remained opposed. And performance on the electoral map may not offer historic protection against impeachment. President Richard Nixon won in a landslide of 49 states in 1972 but two years later had to resign to avoid being impeached and removed.

A day of fast moving developments

Each day since the Ukraine story broke open last week has unfolded in volleys of breaking news stories and head snapping developments that have created a sense of siege around the White House. The pace heated up another few notches on Monday.

Giuliani was dragged directly and inevitably into the Democratic impeachment machine after he was ordered to produce documents relevant to Ukraine by three House committees.

In a statement, a Trump-appointed intelligence community inspector general rejected the central plank of the President's case that the whistleblower was relying on hearsay.

The inspector general said the person had "official and authorized access to the information and sources" referenced in his complaint, direct knowledge of certain alleged conduct and subject matter expertise.

Another key Trump lieutenant, Pompeo, is getting sucked in to the drama, after it emerged that he was on the now notorious July 25 call between Trump and Zelensky. It seems a matter of time before the secretary of state is called to testify.

In a related development, CNN reported Trump personally urged Australia's Prime Minister to help investigate the decisions that led the FBI to open its Russia inquiry involving his 2016 campaign, an official familiar with the conversation told CNN. Trump leaned on Scott Morrison at the suggestion of Attorney General William Barr, who is being drawn further into Democratic sights as they probe the administration's alleged abuse of power. The White House countered that Trump merely asked for introductions so officials could pursue an already announced Justice Department inquiry.

CNN's Jamie Gangel reported that Trump was often unprepared for such calls with foreign leaders, and officials needed to "babysit" the President, who sometimes said embarrassing and inappropriate things to his counterparts.

GOP Senate Majority leader Mitch McConnell said on CNBC that he would have no choice but to convene a Senate trial to determine Trump's fate if he was impeached by the House. The comment shot down Washington scuttlebutt that McConnell might simply ignore a House impeachment vote.

Giuliani warned of serious consequences

The House committee chairmen warned Giuliani that a refusal to comply would trigger serious consequences.

"Your failure or refusal to comply with the subpoena, including at the direction or behest of the President or the White House, shall constitute evidence of obstruction of the House's impeachment inquiry and may be used as an adverse inference against you and the President," the chairmen wrote in a joint letter to the former New York mayor.

Giuliani could seek to shield himself behind attorney-client privilege and the White House could potentially try to invoke executive privilege given its past such expansive claims.

But it is not clear how such claims would hold up in court -- since Giuliani has spilled plenty of detail about his dealings with Ukraine in freewheeling media appearances that may constitute a waiving of privileges.

"I don't see what the privilege is here that prevents him from providing information that is lawfully and appropriately subpoenaed by these three different committees," said Preet Bharara, a former US Attorney for the Southern District of New York who was fired by Trump.

"Rudy Giuliani and others in support of the President have gone on television day after day after day saying as the thrust of their argument here that the whistleblower relies on hearsay information, second hand information," said Bharara, who is now a senior CNN legal analyst.

Bharara told CNN's Erica Hill that Giuliani was "thereby begging people to do exactly what has been done here -- to get direct information and direct evidence."