Throughout their long - and at times pointed - confirmation hearings, Senator Jeff Sessions, former ExxonMobil chief executive Rex Tillerson and retired Marine Corps General James Mattis comported themselves in a graceful and respectful way.

They showed themselves to be thoughtful, patient and deliberate, and they retained a sense of humour and composure even in the face of marginalised protesters, tough questioning and pushback from cranky senators.

It was a reassuring sight, especially when compared with the news conference President-elect Donald Trump held this week, which was acrimonious and at times outright belligerent, especially by White House news conference standards.

So how do we reconcile Mr Trump's often peevish, aggressive nature with the cool, calm and collected demeanour of three of his most vital Cabinet nominees?

The US attorney-general, secretary of state and defence secretary are three of the most important positions in any president's Cabinet. Whether intentionally or not, Mr Trump has chosen leaders to fill these positions who share many of his policy positions, but who are definitely not made in his image.

Perhaps Mr Sessions, Mr Tillerson and Gen Mattis complement some of Mr Trump's weaknesses. Is that part of his design for his Cabinet? Regardless, their nominations should reassure those who may be uneasy about Mr Trump's modus operandi.

Where Mr Trump is brash and says what immediately comes to his mind, Mr Sessions, Mr Tillerson and Gen Mattis are poised and careful in choosing their words.

Mr Trump has shown that he can and will change his opinion based on gut reactions, whereas his Cabinet nominees seem much more grounded and calculated in their positions. Mr Sessions repeatedly emphasised that he will abide by the rule of law, regardless of his personal feelings on any given topic. Mr Tillerson would not be coaxed into using labels, rendering judgment on other cultures or speaking before he had all the facts. Gen Mattis demonstrated that he is entering the job without any biases and is not predisposed to anything approaching recklessness.

None of them was even tempted to take the bait. There is nothing half-cocked about the nominees we have seen testify so far.

One could believe that Mr Trump and his Cabinet nominees are engaged in a reverse "good cop, bad cop" routine: Mr Trump says what he wants to say to get a rise and provoke a reaction, and his Cabinet will follow on with precise manners and policies that will supply effective governance and project reassuring images at home and abroad.

It is being widely assumed that Mr Trump is planning to give his Cabinet "unusually wide latitude" to carry out the objectives of their offices as they see fit.

And as we have seen this week, Mr Sessions, Mr Tillerson, Gen Mattis and others are opinionated, strong-willed leaders in their own right who will not hesitate to challenge the president when they think he is wrong and will pursue policies they think are important for this country.

If Mr Trump is going to pour gasoline on the flames and really shake things up in Washington, it seems that his Cabinet is prepared to control the flames before an out-of-control inferno erupts.