Now's he's getting close to the point of no return with his replacement.

The bureau's public call for the White House to halt publication of a Republican memo condemning its conduct in the Russia investigation puts FBI Director Christopher Wray in open conflict with the President -- and his job on the line.

The statement expressing "grave concerns" about the release of the memo, possibly as soon as Thursday, was more significant than the usual wrangling inside the US government over the release of intelligence material.

It represented a strong statement of independence from Wray, and a firm defense of his bureau that comes at the risk of infuriating the President, who has a record of demanding personal loyalty from top intelligence officials.

"He is putting his job before loyalty to the President," former US Attorney Preet Bharara told CNN, outlining a scenario that has often not ended well for top officials in the law enforcement community during the Trump administration.

Trump is telling associates that he believes the memo alleging the FBI abused its surveillance tools could help discredit the Russia investigation , multiple sources familiar with White House discussions told CNN reporters.

He is also upset about the FBI statement and angry at Deputy Attorney General Rod Rosenstein, who is overseeing the investigation of special counsel Robert Mueller, the sources said.

Clash between White House, intelligence community

But the showdown is about more than a memo -- it is a symptom of the intense crisis of trust between Trump and his own intelligence agencies, even those led by his own appointees. It is playing out against a coordinated attempt by the President and allies to discredit the Russia investigation. And ultimately, this latest tussle is rooted in the President's expressed belief that a "deep state" cabal in US spy and law enforcement agencies is conspiring against him in order to invalidate his 2016 election win.

The FBI is concerned that the memo, produced by Trump ally Devin Nunes, the chairman of the House Intelligence Committee, is inaccurate, distorts facts and could compromise classified intelligence. Late Wednesday night, the committee's top Democrat, Rep. Adam Schiff, injected new drama into the standoff, accusing Nunes of sending a "materially different" memo to the White House than the version on which the committee voted. A spokesman for Nunes said the changes included minor "grammatical fixes" and edits requested by the FBI "and by the minority themselves."

"Not only do they have those concerns, but that they are stating them publicly, I guess in a manner in defiance of the President, is not something I have seen before," said Bharara, who is now a CNN commentator.

The confrontation between the White House and Wray escalated on another frenzied day in Washington, when revelations from the Russia probe and ominous signs of a building crisis over its outcome seem to come by the hour.

CNN reported that Trump asked another appointee, Rosenstein, in December where the Russia investigation -- which he oversees -- was heading, and whether he was "on my team."

The incident appeared to be yet another occasion when Trump may have crossed traditional firewalls between the White House and the FBI designed to shield the agencies from accusations of political interference.

Fired FBI chief James Comey testified last year that Trump asked him for a loyalty pledge. The President also asked former deputy FBI director Andrew McCabe, who resigned this week, who he had voted for in the 2016 election, The Washington Post reported last week.

Bracing for memo's release

Wednesday's events thickened the plot surrounding Mueller's probe, which is examining whether Trump obstructed justice in his firing of Comey and whether his campaign team colluded with Russia's meddling in the election.

The revelations appeared to add new anecdotal evidence to suspicions that the White House and allies on Capitol Hill are politicizing intelligence and crushing long established norms in order to protect the President.

Washington is on tenterhooks for the release of the Nunes memo, which Republicans say shows a dossier about Trump and Russia written by a former British intelligence agent was misused to secure a surveillance warrant for former campaign foreign policy adviser Carter Page.

Trump told a lawmaker after the State of the Union address Tuesday that he would "100%" release the memo. Chief of staff John Kelly said on Fox News Radio it would be released "pretty quick." White House officials told CNN's Jeff Zeleny that the memo could be out as early as Thursday. But it was unclear if the FBI's vehement public objection, following personal appeals to top White House staff by Wray and Rosenstein would change minds in the West Wing. Former CIA director James Woolsey told CNN Wednesday that it was possible the showdown could be defused by making redactions to the document.

The memo, however, has become such a political cause celebrate among conservatives that it would be extraordinarily difficult politically for Trump to back down, even if he cites national security concerns.

In a statement, the FBI said it has grave concerns about "material omissions of fact that fundamentally impact the memo's accuracy."

Democrats say the GOP selectively used intelligence to misrepresent how the dossier was used and to cast the FBI in a bad light.

Nunes pushed back, saying that it was not surprising that the FBI and the Justice Department were raising "spurious" objections to letting the American people know the truth about their surveillance "abuses."

Other Republicans insisted the memo would demonstrate there was serious wrongdoing at the FBI and the Department of Justice that the public needed to see.

"It is going to show FISA abuse took place and there was misconduct at the highest levels of both agencies," New York Republican Rep. Lee Zeldin told CNN's Erin Burnett on Wednesday.

Questions over panel's impartiality

The alliance between Nunes and Trump raises the question of whether the House committee, under a chairman who played a key role on the transition team, has now ceded its oversight role and become a tool in the political attacks on the FBI by the President.

Nunes was already a controversial figure because he dropped a bombshell last year by claiming that Trump campaign officials had been swept up in surveillance by US intelligence agencies and rushed to brief Trump.

In a bizarre twist, it only emerged later that he actually got the information in the first place from Trump aides, raising questions over whether he was taking part in an elaborate plot to discredit the FBI investigation.

"It almost seems like the chairman of the House Committee on Intelligence acts as an agent of the White House," former Director of National Intelligence James Clapper told CNN's Jake Tapper on Wednesday.

But Nunes is not acting alone. On Tuesday, House Speaker Paul Ryan, who was once often critical of Trump but has emerged as an important ally, said he backed putting out the memo.

Questions about the motives of the White House and Nunes were bolstered on Wednesday with the release of a transcript of a House Intelligence Committee hearing on the Republican memo.

In one exchange, Nunes hedged when asked by Democratic member Mike Quigley whether his staff wrote the memo with conversations or consultations with anyone at the White House.

"I would just answer, as far as I know, no," Nunes replied.

However the showdown turns out, it is certain to further strain relations between Trump and intelligence and judicial authorities.

"This is about a unique experience when a Republican president and a Republican congressmen, tell us that a Republican Department of Justice and a Republican FBI are are actually representative of the deep state," said Phil Mudd, a former CIA and FBI official who is now a CNN commentator.

"It is us versus them and the President has said, 'if you don't believe in me, you are off the team.'"