One of the ‘adults in the room’ at the White House has been punted from the room where it happens.

US President Donald Trump has sacked America’s top diplomat Rex Tillerson via Twitter after 14 months as secretary of state.

Some analysts were surprised Tillerson lasted as long as he did.

There is not much love lost between the pair; Tillerson has previously refused to deny calling Trump a ‘f***ing moron’ and didn’t thank him at his final press conference.

The 65-year-old former ExxonMobil chief executive’s dismissal – jokingly dubbed ‘Rexit’ – marks the departure of another moderate influence who supported America’s strong relationships with allies.

CIA director Mike Pompeo is set to take over the reins.

He’s a former Kansas congressman who swept into politics on the Tea Party Republican wave, and before that served as an army tank commander.

The 54-year-old is considered hawkish and one of the most conservative choices for the secretary of state role in history.

Prime Minister Malcolm Turnbull and Foreign Minister Julie Bishop have talked up a ‘seamless transition’ but could be putting on brave faces.

‘We know him very well. He’s a great friend of Australia,’ Turnbull said of Pompeo.

And Bishop told reporters: ‘We had a very good working relationship with Rex Tillerson and I’m confident that will continue under Mike Pompeo.’

Back in December, when speculation was rife of an imminent Tillerson departure, Bishop said she’d be sorry to see him go because he had built up much trust and respect in Australia and the Indo-Pacific.

Former foreign minister Bob Carr said his removal signals a shift to the right and a harder line.

‘The idea that (Trump) is being controlled by the adults in the room … has got to be revised,’ he told Sky News.

So what does this mean for Australia?

Former ambassador to the US Kim Beazley believes the musical chairs will have little impact on bilateral ties.

But head of the ANU’s Strategic and Defence Studies Centre John Blaxland warns the disruption to established professional relationships creates a bow wave effect.

‘It will put our relationship in a more precarious position,’ Blaxland told AAP.

Turnbull and Bishop had been working hard to keep the US alliance on an even keel under an unpredictable Trump.

‘Their job’s gotten an increment harder,’ Blaxland said.

He predicts there could be even more pressure for Australia to carry out a freedom of navigation naval exercise within 12 nautical miles of Chinese-built artificial islands in the South China Sea.

Beazley thinks Tillerson’s exit creates a circuit breaker.

‘My reaction is relief – basically the bad relationship between Tillerson and Trump had effectively taken the state department out of the equation,’ Beazley told AAP.

He predicts the bureaucrats’ expertise will be brought back in from the cold under Pompeo – something especially important ahead of talks between Trump and North Korean leader Kim Jong-un.

Blaxland disagrees, predicting there will be a further corroding of the department and Trump’s small pool of talent has now become shallower.

‘We are now seeing President Trump surround himself with people who are like-minded,’ Blaxland said.

‘Who is saying to President Trump, ‘Maybe you want to think again?’ ‘

He predicts Trump will now be relying more heavily on gut instinct, which is ‘pretty scary’.

Before being given the boot Tillerson had singled out Russia over a nerve agent attack carried out on British soil. While this view aligned with the UK assessment it was at odds with the White House stance.

‘Tillerson finally stood up to Trump on the question of Russian influence and is removed. This is a grave development,’ Blaxland said.

Meanwhile, he expects Beijing will view the saga with a mixture of smirks and nervousness.

‘I think they’re relishing the disorder and enjoying this apparent implosion of the American political system,’ Blaxland said.

‘It’s very heartening for President Xi (Jinping) who has just made himself president for life because he can now talk about order … versus the disorder that is evident in the US system.’