US President Donald Trump's administration has seen significant turnover among senior officials / © AFP/File
National Security Advisor John Bolton, fired by US President Donald Trump on Tuesday, is the latest member of his administration to be shown the door.
Dozens of White House aides -- from attorney general Jeff Sessions to press secretary Sean Spicer and chief of staffs Reince Priebus and John Kelly -- have either left or been sacked from their positions since Trump took office on January 20, 2017.
Here is a sampling of senior departures among his intelligence, foreign policy and national security teams:
- Intelligence -
Dan Coats, a former Republican senator from Indiana, stepped down as Director of National Intelligence on August 15.
Coats was viewed as apolitical and enjoyed bipartisan support, but did not see eye to eye with Trump on a range of issues and at times appears to have been kept in the dark by his administration.
Director of National Intelligence Dan Coats did not see eye to eye with President Donald Trump on a range of issues / © AFP/File
He backed the US intelligence community's conclusion that Russia interfered in the 2016 election that brought Trump to office -- something the president is loath to acknowledge -- and also disagreed with his decision to hold a two-hour closed-door meeting with Russian President Vladimir Putin in 2018.
Coats also said he does not believe North Korea is willing to give up its nuclear arsenal, as the president does, and warned that the Islamic State group -- despite Trump's assertions to the contrary -- was hardly vanquished and could easily rise again.
- Foreign policy -
Trump's first secretary of state, Rex Tillerson, was fired in March 2018, ending a rocky tenure for the former Exxon chief executive as the nation's top diplomat.
Top US diplomat Rex Tillerson was fired by President Donald Trump after a rocky tenure of less than 14 months / © AFP/File
Tillerson was frequently at odds with the mercurial president and they notably disagreed on his decision to withdraw from the Iran nuclear deal.
During Tillerson's brief stay at Foggy Bottom, he frequently found himself out of the loop and caught unawares by policy shifts announced in Trump tweets.
Since leaving office, Tillerson has said Trump was undisciplined and sometimes asked him to do things that were illegal.
Nikki Haley, the US ambassador to the United Nations, left the administration at the end of 2018.
US ambassador to the United Nations Nikki Haley was 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 / © AFP/File
While at the UN, the former governor of South Carolina was an astute advocate for Trump's foreign policy, using forceful language against North Korea, Syria and Iran.
She was also unafraid to speak her mind and earned a reputation for standing up to Trump when she felt it was warranted.
- National security -
John Bolton, fired by President Donald Trump, was his third National Security Advisor / © AFP/File
Trump has had three National Security Advisers since taking office -- Bolton, H.R. McMaster and Michael Flynn.
Trump announced the hawkish Bolton's firing on Tuesday, saying he "disagreed strongly with many of his suggestions."
Flynn, a retired lieutenant general, lasted only 22 days in the position. He was being investigated for his contacts with Russians when he was removed and eventually pleaded guilty to lying to the FBI.
Retired general Michael Flynn lasted just 22 days as President Donald Trump's national security advisor / © GETTY IMAGES/AFP/File
Flynn's replacement, McMaster, also a lieutenant general, lasted barely a year.
McMaster never really clicked with the president, who bristled at his echoing the US intelligence establishment consensus that Russia meddled in the 2016 election.
Trump's Defense Secretary, James Mattis, a retired Marine Corps general, quit in December following a dispute with the president over US policy towards Syria.
Defense Secretary Jim Mattis resigned in December 2018 / © GETTY IMAGES/AFP/File
In a terse resignation letter, Mattis told Trump he was stepping down so he could have a defense secretary "whose views are better aligned with yours."
Mattis, in his first public comments since leaving, said recently that he had to step down after his "concrete solutions and strategic advice, especially keeping faith with our allies, no longer resonated" with the US leadership.