She bad-mouthed the defense secretary. She was the hatchet woman for John R. Bolton, the famously combative national security adviser, and drove out staff members from the National Security Council who were deemed insufficiently conservative or loyal.
But in disparaging two members of Melania Trump’s staff who traveled with Mrs. Trump, the first lady, on her trip last month to Africa, Mira Ricardel, a deputy national security adviser, apparently went too far.
In a White House where the drama has been constant, but almost always behind the scenes, an email to reporters on Tuesday from Stephanie Grisham, a spokeswoman for the first lady, was unusually direct: It is the position of the Office of the First Lady that she no longer deserves the honor of serving in this White House.
The email was sent less than an hour after Ms. Ricardel appeared at an official White House event with President Trump.
There were nonetheless conflicting reports by late afternoon on whether Ms. Ricardel had actually been fired. The Wall Street Journal reported that she was brusquely escorted off the grounds of the White House, only to be corrected an hour later by two White House aides, who said that Ms. Ricardel, who could not be reached for comment, was still employed.
For weeks, Mrs. Trump had warned her husband’s aides that Ms. Ricardel, who is widely distrusted among West Wing staff, was spreading negative stories, including about Mrs. Trump.
But the fact that Ms. Ricardel was in limbo on Tuesday reflected an unusual amount of muscle-flexing by the first lady who normally avoids internecine palace intrigue as well as the limits of her influence. It also showed the obstinance of Ms. Ricardel’s boss, Mr. Bolton, who has a reputation as a shrewd player in a chaotic White House, and someone who is not intimidated, even by the president’s wife.
Mrs. Trump’s problems with Ms. Ricardel seem to date to the first lady’s trip to Africa in October, according to people with direct knowledge of the situation.
Ms. Ricardel had announced the trip before it was fully planned, according to one of the people, and then threatened to pull resources for it after learning that she did not have a seat on Mrs. Trump’s plane. After the trip ended, Ms. Ricardel made accusations of inappropriate behavior by Mrs. Trump’s most trusted staff members, including Lindsay Reynolds, the first lady’s chief of staff claims that a person close to the first lady said were false.
A fixture in Republican foreign policy circles, Ms. Ricardel has honed a reputation as a hawk on policy and as a hard-edge bureaucratic infighter. During the early 1990s, she advised Senator Bob Dole on the Balkans, drawing on her own Croatian background, and later worked for Defense Secretary Donald H. Rumsfeld in President George W. Bush’s administration.
After supporting Mr. Trump for president, she was named to head his Pentagon transition team. In that capacity, she clashed with Jim Mattis, Mr. Trump’s choice for secretary of defense, stopping him from hiring Anne Patterson as under secretary of defense for policy, and rejecting more than a dozen of Mr. Mattis’s other proposed nominees for that job.
Mr. Mattis, in turn, later tried to block Ms. Ricardel when she was considered for posts in the Trump administration, though she eventually served as under secretary of commerce for export administration before Mr. Bolton brought her to the National Security Council.
The drama surrounding Ms. Ricardel was the highlight of a day of rampant speculation about personnel moves that Mr. Trump might be contemplating.
Three people said that Mr. Trump is almost certain to fire Kirstjen Nielsen, the secretary of homeland security, who has long been a target of the president’s displeasure. And Mr. Kelly’s fate is believed to be tied to what happens to Ms. Nielsen.
Inside the White House, removing Ms. Nielsen is seen as a way for Mr. Trump to push out Mr. Kelly, who was the president’s top aide when he was secretary of homeland security, without actually having to fire him. Nick Ayers, the chief of staff to Vice President Mike Pence, is seen as a prospective replacement for Mr. Kelly, if he leaves.
Mr. Ayers is favored by Mr. Trump’s son-in-law, Jared Kushner, and daughter Ivanka Trump, both of whom serve as West Wing advisers. Mr. Trump’s oldest son, Donald Trump Jr., has also told friends that he sees Mr. Ayers as competent, a stamp that the Trump family has not always affixed to people working for their father.
Mr. Ayers did not travel as originally planned with Mr. Pence on his official trip to Asia this week, two White House officials said. And another prospective chief of staff, Mick Mulvaney, who already leads two agencies and who had been seen as campaigning for the chief of staff job, has told aides that he is no longer interested.
Several people working in the White House have expressed concern to the president about putting Mr. Ayers in that role, and they have warned that some staff members might quit because of it.
Mr. Trump hates interpersonal confrontation, and he often lets aides he does not like remain in their positions for uncomfortably long periods, meaning any changes could still be weeks away, if at all, including doing something about Ms. Ricardel, the people close to the president cautioned. Mr. Trump, however, has grown increasingly suspicious that Mr. Kelly and his closest aides are leaking stories.
Mr. Kelly has defended Ms. Nielsen to the president, and has tried to shield her from criticism from other cabinet members. Though some of Mr. Trump’s allies regard his views and treatment of her as unfair.
Ms. Nielsen has struggled to explain to the White House the complexities of border security, and one department official said Ms. Nielsen has even pushed back on many measures suggested by immigration hard-liners, though she has forged ahead with efforts to limit immigration using other contentious policies. The most recent effort is a proposal that would deny asylum to anyone who arrived in the country illegally.
The employees believe Ms. Nielsen’s fate was sealed with the release of the agency’s border enforcement data over the past two months, which showed that while the overall number of people apprehended at the border remains low, the number of families making the trek to the United States has grown.