Washington (CNN) Even as the White House appears to settle on the legal tactics to stave off Democrats' impeachment demands , uncertainty and unease over Trump's messaging approach remains high among his Republican allies, who see the ever-growing inquiry consuming the White House.

Trump has offered scant indication he is turning his focus to governing, despite his lawyers writing in a letter to Democrats that "he remains focused on fulfilling his promises to the American people."

Instead, the President has spent hours tweeting about the impeachment and lighting up the phone lines of his allies on Capitol Hill -- including Senate Majority Leader Mitch McConnell , to whom he's stressed the importance of Republican unity.

In private, Trump is increasingly leaning on the Republican leader in the Senate. In a return to the President's panicked behavior during the height of the Mueller investigation, Trump is calling McConnell as often as three times a day, according to a person familiar with the conversations.

McConnell has told a small number of Republicans about the President's calls.

"This story, based on a single anonymous source, is categorically false. Leader McConnell never said anything like this," Doug Andres, a McConnell spokesman, said.

Trump has been lashing out at GOP senators he sees as disloyal, according to the person familiar with the conversations, telling McConnell he will amplify attacks on those Republicans who criticize him.

McConnell faces his own dilemma of having to preserve the Republican majority in the Senate, while also placating an erratic President who demands nothing short of total loyalty. That will become harder as more details about Trump's dealings with Ukraine trickle out.

Trump has already demonstrated his willingness to go after Republican defectors. After Sen. Mitt Romney, R-Utah, said it was "wrong and appalling" for Trump to suggest Ukraine and China investigate Joe Biden, Trump unloaded, calling Romney a "pompous ass" and suggesting Romney himself be impeached.

Trump has also been mistrustful of Republicans who are reticent to defend him publicly, often lamenting that Democrats are much better at staying in line with their party heads than his own.

Refusing to cooperate

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A letter from White House lawyers on Tuesday made clear Trump plans to wage war on the impeachment effort, refusing to cooperate with what it described as an illegitimate effort to reverse the 2016 election. An announcement that Trey Gowdy, the former South Carolina congressman, was joining Trump's outside legal team was a signal of the growing recognition the President will require additional help combating the impeachment threat.

Trump had initially been resistant to the suggestion that he hire additional attorneys, believing he was well positioned to combat Democrats as they advanced their impeachment probe without outside help. But after a lengthy meeting with Gowdy in the Oval Office, and much wheedling from Gowdy's allies, the President was convinced he needed an aggressive fighter, such as the former House Oversight Committee chairman who led the Benghazi probe.

Trump's confidants had urged him for weeks to find another voice who could represent him on television, warning that his personal attorney Rudy Giuliani was doing too much damage.

Trump's focus on the impeachment issue is plain, even as his allies encourage him to train his attention on other issues. On Wednesday, as former Vice President Joe Biden came out in favor of impeachment, Trump had responded on Twitter before Biden's speech had even concluded. And speaking in the Roosevelt Room, Trump went off-script to link a regulatory announcement to his ongoing predicament.

"No American should ever face such persecution from their own government," Trump said, reading from a script, before looking up from his paper: "Except, perhaps, your President."

Internal strife

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Internal disputes, long rife in Trump's West Wing, have also heightened the sense of disorder at Trump's approach to impeachment. Trump's son-in-law and senior adviser Jared Kushner is seen by many aides as leading the impeachment strategy efforts. A source close to the President's impeachment team said Kushner is playing a "growing role" in how the White House handles the response, though other officials said much of the response will be left to "Jay and Trey," a reference to Gowdy and Jay Sekulow, members of the outside legal team.

Others say the only real point person is Trump himself, who has tweeted furiously on the subject for the past three days.

Mick Mulvaney, the acting chief of staff, has remained largely under the radar as the impeachment proceedings unfold. But Gowdy's hiring is evidence that Mulvaney -- who is close friends with his former House colleague and advocated on Gowdy's behalf -- also has some leeway in overseeing the strategy.

In an effort to channel some of Trump's frustrations, campaign aides have scheduled a spate of campaign rallies over the next week, including one in Minnesota on Thursday and in Louisiana on Friday. Trump announced the Louisiana rally on Twitter as his campaign was still confirming the venue. They believe Trump's anger at Democrats and arguments against impeachment will be amplified when delivered before a receptive audience.

Yet that dynamic is partly what concerns many of Trump's allies, who worry the President's obvious fixation on the impeachment matter is causing him to lash out in unhelpful and erratic ways.

In private, Trump has vacillated between telling confidantes the impeachment effort will benefit him politically to complaining it will stain his legacy. As Trump reflexively reacts to each development, many Republican lawmakers and others who the White House relies upon to defend the President have gone silent.

Others have expressed concern that Trump isn't taking the impeachment inquiry seriously enough, even as polls increasingly show Americans support it.

"I believe it's a mortal threat to the presidency. He should treat it that way," said Chris Ruddy, a friend of Trump's and the CEO of Newsmax, in an interview with CNN's Christiane Amanpour . "The number of people saying the President should be impeached is increasing. Not significantly, but moving in a bad direction for the President. I think it should be treated very seriously."

'All bulls***'

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A Trump ally who spoke with the President recently said Trump's view on impeachment is "it's all bulls***" and he believes he and his GOP allies are well positioned to fight back politically. Trump was "praising the (Republican National Committee) targeting those Trump-district Democrats," the source said. "He seemed in good spirits."

The RNC is targeting roughly 60 Democrats with a "stop the madness" campaign through paid media and earned media, including conducting press conferences, crashing town halls and holding demonstrations.

McConnell has said little publicly about impeachment since the inquiry began. He admitted last week in an interview with CNBC that he would "have no choice" but to take up a trial if the House voted to impeach Trump -- a point he's made to Trump in their phone conversations, according to one person with knowledge of the situation.

But on strategy, McConnell's said nothing more to the Republican conference, which has been in recess for two weeks. That, say multiple people with knowledge, reflects McConnell's "watch and wait" approach to all controversies, including impeachment.

While at home on recess the past two weeks, many Senate Republicans have stayed quiet on the House Democrats' impeachment inquiry. But some have already laid out messaging that could gain steam once everyone returns next week, including admitting that while Trump's call with Ukraine was perhaps inappropriate, it does not rise to impeachable conduct.

CNN's Sara Murray contributed to this report.