The only mystery about Donald Trump's abrupt firing of his Secretary of State is why Rex Tillerson did not leave much earlier. A man who had served his whole career in the oil company ExxonMobil, he did not fit into the cruel world of Washington politics and he never saw eye to eye with the president. Indeed, he pursued his own policies to the point of insubordination.
On major issues the chief diplomat was publicly at odds with Mr Trump. This was most clear with regards to the Iran nuclear deal, which the president has called "the worst deal ever", but which his secretary of state preferred to maintain, in the absence of anything better on offer. Mr Tillerson wanted to stick with the Paris climate change agreement and the president wanted out. He sought to end the Gulf states' boycott of Qatar in defiance of his boss's wishes. He even broke the White House rule that no one should criticise Russia.
Lacking any grand ideas of America’s place in the world, Mr Tillerson treated the State Department as a business that needed drastic budget cuts in the form of “efficiency savings”, but never articulated what their purpose was.
As long ago as August last year State Department veterans were dismissing him as an "abject failure" and his time seemed up in October when it was reported that he had described Mr Trump as a moron, a report he notably failed to deny. His end was humiliating for a holder of one of the great offices of state – he learned of his dismissal from a tweet while hurrying back from a tour of Africa.
The Tillerson episode – the wrong man in the job, fired in the wrong way, at the wrong time – has been dismissed as another example of the chaos in the White House. That is too easy. Rather it should be seen as a sign that after a year in office Mr Trump has gained the confidence to create a team around him that he feels at ease with.
It is worth looking back to the team that Mr Trump took to the World Economic Forum in Davos, Switzerland, in January. It was packed with people who impressed the global elite who gather there every year. Some of them heaved a sigh of relief that the Trump team – the so-called “grown-ups” – were people they could do business with. The president’s alarming tweets could be safely ignored.
Among the Trump entourage were Gary Cohn, a free-trader and chief economic adviser to the president; Mr Tillerson, a businessman with a traditional view of America's place in the world; Dina Powell, a well-regarded holdover from the Obama National Security Council, and Lieutenant-General HR McMaster, National Security Adviser who is the embodiment of the American soldier-intellectual.
Mr Cohn has now resigned, having lost a power struggle over trade to the America First group who support the president’s imposition of tariffs to protect US industry; Ms Powell has quietly arranged her departure; Mr Tillerson has been sacked and the American media never stop predicting when Gen McMaster will follow him out.
Only a month ago a Washington insider could state with total conviction that none of Mr Trump’s foreign and national security team shared his world view, with the exception of those in charge of trade. The top people in the Pentagon, the State Department and the National Security Agency spent their time ignoring the president or trying to moderate his views. That is changing.
Having a trade team who are on his wavelength has encouraged Mr Trump to trust his instincts which, in his view, propelled him to the White House in defiance of expert opinion and received wisdom. Peter Navarro, Mr Trump's nationalist-minded trade adviser who drove the free marketer Mr Cohn out of the White House, told Bloomberg earlier this month that his job was to support the president's intuitions with economic arguments. "And his intuition is always right in these matters."
Mr Tillerson's nominated successor, the hawkish Conservative Mike Pompeo who has risen under Mr Trump from congressman to director of the CIA, will have no difficulty connecting with the president and articulating an America First foreign and trade policy. Mr Trump has said of him, "we have a very similar thought process."
There is little doubt that Mr Trump's long-held wish to withdraw from the 2015 Iran nuclear deal, the Joint Comprehensive Plan of Action, will happen in May, when he has to decide whether to re-impose sanctions. Mr Pompeo is an Iran hawk who spared no effort to undermine the agreement when he was in Congress. He has also made clear his preference for regime change in North Korea, which may cast a shadow over Mr Trump's planned summit with Kim Jong-un in May.
Ahead of the summit, the president will need a lot of coaching. So far the North Korean leader has deftly outplayed the Americans, and the under-staffed US diplomatic team will need to go into overdrive to catch up.
But avoiding a diplomatic disaster may not be easy. It may take 30 days for Mr Pompeo to be approved by the Senate. Meanwhile, Mr Trump’s intention to renounce the Iran nuclear deal negotiated by the previous administration will not inspire confidence in the North Koreans that Washington can be trusted to keep its word, but probably they have no illusions on that score.
Diplomats will relish the fact that the question of who is in charge of foreign policy is resolved. Mr Trump who has cut a somewhat lonely figure in the White House in recent weeks is looking to surround himself with more like-minded people. That, however, does not change the basic political calculus. The fate of Mr Trump's presidency depends less on who he appoints than how Americans vote in the congressional elections in November. And the Special Counsel, Robert Mueller, who is investigating allegations of Russian interference in the 2016 presidential election in support of the Trump campaign, is still prowling in the background.