The much-anticipated sacking of Rex Tillerson this week was accompanied by the equally widely trailed appointment of Mike Pompeo. 

In almost every regard, Donald Trump’s pick for Secretary of State is the polar opposite of the man he replaces. 

Mr Tillerson had never held a government post before becoming America’s chief diplomat. By contrast, Mr Pompeo is the ultimate Washington insider.

After a spell in the military, the former businessman was elected to Congress in 2010 and became a vocal member of the hard-right Tea Party movement.  

When the US ambassador to Libya and three fellow Americans were murdered in Benghazi in 2012, Mr Pompeo was one of the leading attack dogs – from his perch on the House Intelligence Committee – into then-Secretary of State Hillary Clinton’s conduct. 

 His combativeness endeared him to Mr Trump, who picked him to become CIA director in 2016.

Unlike Mr Tillerson, Mr Pompeo swiftly established a strong personal rapport with the new president.

In an indication of his political savvy, he often chose – unusually for a CIA director – to deliver the president’s daily intelligence briefing in person.

Those briefings, which eschew long reports in favour of graphic presentations to lengthen Mr Trump’s notoriously short attention span, are reported to be one of the highlights of the president’s day. 

Crucially, whereas Mr Tillerson’s loyalty to Mr Trump was considered suspect – especially when he failed to deny calling him a “f***ing moron” – Mr Pompeo’s has never been in doubt.

The CIA director has gone out of his way to indulge the president’s fantasy that Russian meddling had no impact on the outcome of the 2016 presidential election. 

And, while Mr Trump is believed to have considered Mr Tillerson’s diplomacy “too establishment”, Mr Pompeo has long shared the president’s Manichean instincts.

“We are always on the same wave length,” Mr Trump said of his nominee.

Mr Pompeo’s belief that the CIA should be “aggressive, vicious, unforgiving, relentless” might equally describe the two men’s view of how America should handle a dangerous world.  

He believes that the threat of “radical Islamic terrorism” requires extraordinary measures: he supports the use of torture and strongly defends Guantanamo Bay.  

He was a staunch critic of the Obama administration’s nuclear deal with Iran and declared days after Mr Trump’s election that he looked “forward to rolling back this disastrous deal with the world’s largest state sponsor of terrorism”.

He is thus likely to encourage – rather than, as Mr Tillerson did, restrain – the president’s desire to rip up the agreement.  

Mr Pompeo’s stance in part reflected his staunch support for Israel. Like Benjamin Netanyahu, he called for any deal with Tehran to be conditional on Iran abandoning its calls for Israel’s destruction. 

However hawkish and hard-line, Mr Pompeo’s foreign policy views show a consistency which the president often appears to lack.

That, at least, may help to counter some of the unpredictability that emanates from the Oval Office.