Trump's revolving door: Nielsen is latest to go

US Homeland Security Secretary Kirstjen Nielsen who is leaving her post after serving as enforcer of President Donald Trump's controversial immigration policies. PHOTO | ALEX EDELMAN | AFP

What you need to know:

  • She would become the front-line defender of the administration's immigration policies.
  • Despite remaining steadfast in her loyalty, her ability was long said to have been questioned by Trump.

Washington

US Homeland Security Secretary Kirstjen Nielsen is leaving her post after serving as enforcer of President Donald Trump's controversial immigration policies.

Dozens of White House aides – from attorney general Jeff Sessions to press secretary Sean Spicer to chief of staff Reince Priebus – have either left or been sacked from their positions since Trump took office on January 20, 2017.

DEPARTURES

Here is a sampling of senior departures:

Kirstjen Nielsen previously served as a cyber security specialist in the Department of Homeland Security (DHS), then as assistant to Trump's first DHS secretary, John Kelly.

When Kelly moved to the White House as Trump's chief of staff in July 2017, Nielsen went with him as his deputy – but by October was back at DHS, this time as secretary.

She would become the front-line defender of the administration's immigration policies and the face of its widely condemned practice of separating migrant children from their parents.

ABILITY QUESTIONED

Despite remaining steadfast in her loyalty, her ability was long said to have been questioned by Trump and her eventual departure – coming months after her mentor Kelly's resignation – was not a shock.

Her loyalty wasn't enough to save her as she resigned Sunday – reportedly under pressure for not being tough enough to enact the president's ever-hardening push against illegal immigration.

Zinke, a former Navy SEAL and ex-member of the House of Representatives, was one of the main executors of Trump's efforts to reduce environmental protections in the United States. He left at the end of 2018.

SCANDALS

He managed to hold onto his post for some two years despite a series of scandals over expenditures, including reports that his department was spending nearly $139,000 to upgrade three sets of double doors in his office – a cost he later said he negotiated down to $75,000.

Kelly, a retired four-star Marine Corps general, has been credited with helping restore a degree of order to the often-chaotic Trump White House before his exit at the end of 2018.

But in the process he clashed with members of the Trump clan, and at times infuriated Democrats with his blunt comments.

Kelly, 68, made it known he did not always love the job -- one of the most vital in any White House – quipping, "God punished me, I guess."

SESSIONS

He left Sessions, a Republican senator from Alabama, was the first member of the Senate to back Trump's insurgent bid in 2015 for the Republican presidential nomination. Trump rewarded Sessions by naming him to head the Department of Justice.

But relations quickly soured after Sessions recused himself from Special Counsel Robert Mueller's probe into whether the Trump presidential campaign colluded with Russia to get him elected.

Trump personally attacked Sessions on several occasions for failing to protect him from the Mueller probe.

Haley, who announced last October that she would leave the administration at the end of 2018, was a shining star from the start.

FOREIGN POLICY

Thrust onto the international stage, she quickly became an astute advocate for Trump's foreign policy, using forceful language against North Korea, Syria and Iran.

The former South Carolina governor was also unafraid to speak her mind, often in fairly undiplomatic language, and built a reputation for standing up to Trump when she felt it was warranted.

Her aggressive criticism of Russia won plaudits, even as she stepped beyond the position held by the White House.

Environmental Protection Agency head Scott Pruitt's tenure was beset by scandal, and Trump pushed him out in July.

A former Oklahoma attorney general with ties to fossil fuel industries, Pruitt was accused of using his position to enrich his family's lifestyle in violation of federal law.

TILLERSON FIRED

Rex Tillerson was fired by Trump last March, ending a rocky tenure for the former Exxon chief executive as the nation's top diplomat.

Tillerson was frequently at odds with the mercurial president. They notably disagreed on the Iran nuclear deal, from which Trump withdrew last May.

During his brief stay at Foggy Bottom, Tillerson frequently found himself out of the loop and caught unawares by policy shifts announced in Trump tweets.

In one of his first public criticisms of the president since stepping down, Tillerson told a gathering in Texas earlier this month that Trump was undisciplined, did not like to read briefing papers and sometimes asked him to do things that were illegal.

Trump shot back on Twitter that Tillerson was "dumb as a rock."

The architect of Trump's nationalist-populist campaign and his election victory, White House chief strategist Steve Bannon was nicknamed the Prince of Darkness and the Shadow President.

LYNCHPIN

His economic nationalism became the lynchpin of Trump policies, even as many of Bannon's other ideas were rebuffed by policy rivals.

Bannon's constant clashes with other advisors became untenable, as did his ties to the extreme right. He left in August 2017.

Michael Flynn, a retired lieutenant general, was being investigated for his contacts with Russians and eventually pleaded guilty to lying to the FBI.

He lasted only 22 days as national security advisor.

Flynn's replacement, HR McMaster, also a lieutenant general, lasted barely a year.

He never really clicked with the president, who bristled at McMaster echoing the US intelligence establishment consensus that Russia meddled in the 2016 election.