Prime Minister Malcolm Turnbull appears to have pulled off an impressive feat of navigation.

Not only has Mr Turnbull successfully charted US President Donald Trump's temperament — notoriously choppier than the South China Sea — but he's helped steer an old alliance closer towards full health.

In doing so, he has made headway in ensuring the insularity threatened by Mr Trump's America doesn't see the United States drift from its security and economic responsibilities in the Asia-Pacific.

Theirs was a relationship that began badly. Very badly.

Mr Turnbull copped it from Mr Trump when they spoke by phone just days after the President's inauguration last year.

Mr Trump told the Prime Minister it was his "worst call by far", berating Mr Turnbull for the refugee agreement he inherited from Barack Obama, which would see the US accept up to 1,250 people now on Manus Island and Nauru.

The President, who'd made immigration one of his campaign battle cries, accused Mr Turnbull of wanting to export the "next Boston bombers".

It was a bruising conversation, made worse when Mr Trump slammed the phone down 25 minutes into a scheduled hour-long call.

But Mr Turnbull held firm on the arrangement with Mr Obama, figuring even a capricious, unpredictable Mr Trump would know when a deal's a deal.

Donald Trump hosted Malcolm Turnbull at the White House. ( Facebook: Malcolm Turnbull )

Turnbull gently educating Trump

Of course, Mr Turnbull has had the weight of history on his side.

Australia and the US have a long history of camaraderie: on the battlefield, the world stage — even the silver screen. They have shared language, values and democratic outlook.

He's judged — not without some risk — Mr Trump has needed an ally and would be urged by others not to offend one of America's staunchest friends.

He wasn't obsequious to Mr Trump's rough complaint about the refugee deal, but patient and firm. As a consequence, it still stands.

Similarly, he's sought to guard Australia against the inward-looking Mr Trump manifesto implied by the "make America great again" motto.

Beneath the hokey veneer has lain a certain purpose. ( AP: Carolyn Kaster )

Mr Turnbull's emphasis on "mateship" — drawn from the 100th anniversary of the Battle of Hamel, when Australian and US troops fought side-by-side for the first time — has appeared twee and jingoistic.

But beneath the hokey veneer has lain a certain purpose.

He's sought to gently educate Mr Trump about America's strategic importance to its ally Australia and its Asia-Pacific neighbourhood, of its role as foil to China.

Regional prosperity and security demands a muscular America — not an insular one.

But there is an abiding sense that an Australian Prime Minister's work watching over Mr Trump will never be done.