Donald Trump's homeland security adviser has become the latest official to leave the White House prematurely, a day after John Bolton joined the president's team as his new national security chief.
As recently as this weekend, Tom Bossert was being dispatched by the administration to the Sunday talk shows to defend Mr Trump's plan to send National Guard troops to the border. He also offered one of the first official US responses to the alleged chemical attack in Syria.
Sarah Huckabee Sanders, the White House press secretary, said Mr Bossert had resigned. "The president is grateful for Tom's commitment to the safety and security of our great country . . . President Trump thanks him for his patriotic service and wishes him well."
However, political observers of the administration linked Mr Bossert's departure to the arrival of Mr Bolton, the former US ambassador to the UN under George W Bush.
"John Bolton wants his own team," said Thomas Wright, an expert at the Brookings Institution. Mr Bolton, Mr Wright said, "distrusts career officials". But the president will face trouble finding outsiders to come in, given that many mainstream foreign policy experts signed an anti-Trump letter during the 2016 campaign.
“One of [Mr Bolton’s] early tests will be whether he can persuade President Trump to relax the ban on the NeverTrumpers,” said Mr Wright.
Mr Bolton started at the White House on Monday and is expected to take a different tack from his predecessor HR McMaster by pushing a more hawkish policy on Iran and North Korea. Together with Mr Trump's newly nominated secretary of state, Mike Pompeo, the group is expected to provide a counterweight to defence secretary Jim Mattis, endangering the future of the Iran nuclear agreement, and raising the prospect of a military stand-off with Pyongyang.
Mr Bossert is one of more than a dozen high-profile officials who have left Mr Trump's administration less than 15 months into the president's first term. In March, Brookings calculated that Mr Trump's White House had a 46 per cent turnover rate for high-profile jobs, versus 24 per cent for Barack Obama and 33 per cent for George W Bush.
Moments of crisis
Inside the White House, Mr Bossert was known as a competent member of Mr Trump's team who was loyal to the president during moments of crisis. For instance, he defended the president when he came under fire last year for remarks about a violent neo-Nazi market in Charlottesville.
He was involved in cyber issues for the administration and also in the administration's response to a string of natural disasters in Puerto Rico, Florida and Texas last year. Mr Bossert, who had regular access to the president, was also engaged in the US response against cyber attacks, including North Korea's WannaCry ransomware attack.
Before joining the Trump White House, Mr Bossert worked as deputy homeland security adviser to President George W Bush – a position that was created after the terror attacks of September 11th, 2001.
– Copyright The Financial Times Limited 2018