An internal White House enemies list of alleged Obama loyalists to be fired early in the Trump administration is a key contributor to a long-running feud between the National Security Adviser H. R. McMaster and White House chief strategist Steve Bannon, two senior administration officials tell The Daily Beast.

Team Trump never acted on the list, the officials said, and now those employees have finished their tenure at the National Security Council and returned to their home agencies.

But fallout over the list—and questions about loyalty to Bannon versus McMaster—led the three-star general to fire two of his top aides, an act that’s landed McMaster in the firing line of Bannon’s alt-right media allies and Russian troll bots, both calling for his ouster.

It’s the kind of personality clash and conflicting lines of authority that ret. Marine Gen. John Kelly has been brought in to quiet as chief of staff. He gave McMaster the go-ahead to remove people whose loyalty he questioned, including NSC intelligence director Ezra Cohen-Watnick and ret. Col. Derek Harvey, the NSC Mideast director. Both had meetings with Bannon throughout their tenure , described as hushed national-security related “chats,” by one senior White House official, without seeking McMaster’s permission beforehand.

Multiple administration sources confirmed to The Daily Beast that these “chats” between Bannon and Harvey and Cohen Watnick vexed Trump’s national security adviser, and contributed to McMaster’s desire to “finally make moves against” them, as one senior official recounted.

A third more junior director, Rich Higgins, disseminated his own paper to senior U.S. officials that argued globalists and leftists were trying to undermine Trump, without showing it to anyone within the NSC first. He was fired by McMaster’s deputy Rick Waddell for presenting his work as administration policy, one administration official said. Another administration official said Higgins shared his paper only with people from the Trump campaign that he’d met in a personal capacity, and that he never got an explanation for why he was being fired. But his firing added fuel to the alt-right ire against McMaster.

Team Trump has fought back with President Donald Trump issuing a statement to defend McMaster. Multiple officials have also pointed out that McMaster kept most other Flynn hires in their posts, appointing military academic Michel Bell to replace Harvey, and elevating the NSC’s Victoria Coates to serve as key aide to Trump’s special envoy to the Mideast Jason Greenblatt.

But that hasn’t satisfied supporters of the fired men from Bannon world. Bannon was removed from his controversial post on the NSC shortly after the end of Flynn’s brief tenure and the start of the McMaster era. For months, the two have butted heads over foreign policy issues, particularly the preferred level of U.S. involvement in the war in Afghanistan—a heated disagreement that has sometimes escalated to raised voices and, as one White House adviser said, “palpably uncomfortable” meetings.

Furthermore, there is, according to multiple senior administration sources, no trust whatsoever between the two men. McMaster has long suspected Bannon of covertly engineering an aggressive leak campaign against him in an attempt to caricature him as anti-Israel and weak on terror—suspicions that persist to this day.

Officials spoke to The Daily Beast on the condition of anonymity because they were not cleared to discuss these sensitive matters. White House press secretary Sarah Huckabee Sanders referred all The Daily Beast’s questions to the NSC, which declined to comment.

Bannon, for his part, is a huge fan of Michael Flynn, Trump’s former national security adviser—a man who was far more sympathetic to the less restrained, right-wing nationalist elements of the Trump administration. President Trump himself has been known to express regret for the need for Flynn’s departure, and has privately expressed his hope that a resolution of the FBI’s investigation in Flynn’s favor might allow Flynn to rejoin the White House in some capacity—a scenario Trump’s closest advisers in and outside of the West Wing have stressed to him is politically untenable, as The Daily Beast previously reported.

And now, some of Flynn’s acolytes appear to be striking back, through leaks to nationalist and America-First-leaning media outlets, leading to yet another guerilla war against McMaster and his allies in recent days influential arms of pro-Trump media. Breitbart, the right-wing news outlet formerly run by Bannon, blared headlines across its homepage on Thursday accusing McMaster of being “deeply hostile” to Trump’s agenda. Gateway Pundit, another prominent pro-Trump news site, derisively dubbed McMaster an arch “globalist.”

And Mike Cernovich, the Alex Jones acolyte and Trump-boosting social media personality, is promoting a website this week devoted to attacking McMaster and trying to publish leaked info about him. (A cartoon that led the website showed McMaster and Gen. David Petraeus dancing on the ends of puppet strings held by billionaire hedge fund manager and bogeyman to the American right George Soros.)

THANK YOU, THERE’S THE DOOR

As with any firing, the Bannon chats weren’t the sole reason either Harvey nor Cohen-Watnick were removed.

With Harvey, his dealings with the Pentagon and State Department had become fractious, two officials said. One Trump official called his personality difficult, but another said the agencies were waging some of their battles against White House through Harvey, slow-rolling his information requests.

But the original sin in McMaster’s eyes was agreeing to look over the so-called enemies list early in the Trump administration, but not informing McMaster that such a list was even being contemplated, two of the senior administration officials explained.

Harvey had been called to the meeting with Bannon to discuss the list by then-White House chief of staff Reince Priebus, one of the officials said. It had been compiled by campaign staffers during the transition, in part by comparing White House staff lists with their social media profiles, noting any anti-Trump posts.

Harvey managed to convince the two men not to act on it, as the staffers in question were temporarily detailed to the NSC by their agencies and would all be gone by the summer.

McMaster found out about the meeting weeks later and berated Harvey for attending what he thought was a Bannon meeting, never giving Harvey a chance to explain the chief of staff had convened it—and that he had argued against firing staff. It was a first strike against him.

(Ironically, White House officials this week have been fearing the existence of an alleged “purge list” of McMaster’s internal adversaries, as BuzzFeed reported.)

Another strike, one of the officials said, was that Harvey let White House adviser Sebastian Gorka sit in on Mideast-related meetings without checking with McMaster.

A third strike occurred the Friday before Harvey was fired, when he met with Bannon again. This time, it was because McMaster had asked staff to set up a chart laying out campaign promises kept and yet to achieve for the Middle East. Bannon’s office walls were covered with those campaign promises so it seemed a logical step, one of the officials said.

Less than a week later, Harvey was fired, but McMaster did hold a farewell party for him at the NSC, and told staff “sometimes brothers disagree,” the administration official said.

Unlike Cohen-Watnick, Harvey is in line for another senior administration post, multiple officials said.

LEAK-A-PALOOZA

Two Trump administration officials were less kind describing the departure of Cohen-Watnick, blaming him for a slew of poisonous leaks about other staff throughout his tenure and since his departure. But another official said Cohen-Watnick was caught in the crossfire between the Bannon and McMaster camps, becoming the scapegoat for leaks and catching blame for them based on circumstantial evidence.

The anti-Cohen-Watnick camp says that days after he was dismissed, a letter from McMaster to Obama National Security Adviser Susan Rice was leaked, in which he informed her that he was extending her security clearance.

Two officials claim that letter was one of a stack of similar letters that Cohen-Watnick, the just-fired NSC intelligence director, had given to McMaster to sign, informing all living national security advisers that their security clearances had been extended—a pro-forma process done by every White House so current leaders can speak to previous ones about classified national security policy, a source close to McMaster explained.

Yet the only letter that was leaked after Cohen-Watnick was fired was the one to Rice, which McMaster saw as an effort to tar him with a connection to the previous Democratic administration, the source explained.

The other White House official, however, says Cohen-Watnick’s office did not handle such matters, and that his office would not have had access to such a letter regarding Rice.

The McMaster leak is part of a pattern of disclosures that McMaster supporters believe is designed to paint him as a leading obstacle to the Bannon World/American First vision for the White House, with some of the ugliest coverage being levied at him by Bannon’s former publishing concern Breitbart.

“H.R. is under a crazy assault from social media,” one of his supporters told The Daily Beast.

A source close to McMaster claims it also follows a pattern of leaks to right-wing blogger Cernovich that he blamed on Cohen-Watnick, in which minor NSC staffers would be called out for anti-Trump infractions like being seen talking to a former Obama official. But the other administration official said that was a frequent accusation leveled by McMaster’s camp at anyone he didn’t see eye to eye with. According to multiple administration sources, it became a source of bemusement among staffers that if one crossed Cohen-Watnick in a staff meeting, a punishing leak to Cernovich would often quickly follow.

Cohen-Watnick did not respond to requests for comment.

UPDATE: This story was updated to reflect input from another White House official.