Even 18 months into his presidency, the world is still having trouble coming to grips with Donald Trump, the most unconventional president ever. Still, he’s not a bad dream from which America will soon wake up, or a fool to be ridiculed.

For someone the legion of critics say is a compulsive liar, he’s been remarkably true to his word.

Especially compared with his predecessor, Trump doesn’t moralise. It’s classic Trump to be openly exasperated by the G7’s hand-wringing hypocrisy.

Unlike almost every other democratic leader, he doesn’t try to placate critics. He knows that it’s more important to get things done than to be universally loved; because all his life, he’s impressed people by doing deals, rather than by setting out to win them over.

Beyond his sprawling pastse and the over-the-top tweets, the holder of the world’s most significant office should always be taken seriously.

Erratic and ill-disciplined though he often seems, there’s little doubt that Trump is well on his way to being a consequential president. On all the evidence so far, when he says something, he means it, and when he consistently says something it will happen.

He said he’d cut taxes. He has, and the American economy is at its strongest in at least a decade. He said he’d cut regulations, and innumerable Obama-era green rules have gone.

He said he’d pull out of the Paris climate change agreement and he has, to the usual obloquy, but no discernible environmental damage.

He said he’d scrap the Iranian deal and that’s happened; so if Iran gets nuclear weapons, at least it won’t be with American connivance.

He said he’d move the US embassy to Jerusalem and that’s been done, without catastrophe.

He said he’d boost defence spending. That’s happening too, and adversaries no longer think that they can cross American red lines with impunity.

He said he’d build a wall with Mexico. It’s bogged down in the courts and congress; but once it’s there, it will be the US version of Australia sending back the boats, and will end up demonstrating that it’s far from humane to let people take advantage of you.

Already, he’s accomplished 64 per cent of the Mandate for Leadership agenda that the Heritage Foundation set for him – not bad at all, compared with just 49 per cent for Ronald Reagan at a similar stage in his presidency!

It’s a pity that he’s kept his promise to pull out of the Trans-Pacific Partnership trade deal; but his concerns shouldn’t be dismissed, because in the short term freer trade can be better for rich people in poor countries than for poor people in rich ones.

Trump thinks that the impact of freer trade has been to make America’s enemies stronger; but as the Harley-Davidson experience shows, global supply chains mean that even “all-American products”, these days, are “made in the world” and the consequence of losing imports can be losing exports too as other countries retaliate.

So far, though, strong rhetoric backed by tough action, hasn’t triggered a full-scale trade war but has forced other countries to address America’s concerns about technology theft and predatory pricing.

Then there’s the nuclear deal with North Korea. Maybe a hitherto brutal dictator – who’s so far murdered his half-brother, an uncle and all his extended family, and had his defence minister blown to pieces by artillery fire – could actually be looking for a way out and for the survival strategy that Trump has provided.

On the other hand, it could also be a latter day version of the Iran deal where pressure is relaxed on a dreadful regime on the basis of promises that are never fully kept – leaving the South Koreans unsure of American support.

That’s the trouble with one-on-one meetings. They might be good for building trust, but they’re bad for making decisions, because each participant has his own version of what was meant.

Still, whatever our judgment on the Trump presidency so far, he’s got two and half more years in the world’s biggest job and has every chance of being re-elected. He is the reality we have to work with.

For Australia, Trump has so far been a good president. Despite a testy initial conversation with Prime Minister Turnbull, he’s honoured the “very bad deal” that his predecessor had done to take boat people from Nauru and Manus Island and to settle them in the United States.

He seems to appreciate that Australia is the only ally who’s been side-by-side with America in every conflict since the Great War, and has exempted our steel and aluminium from the tariffs slapped on many others.

As a country that’s “paid its dues” on the American alliance, we have been treated with courtesy and respect but that’s no grounds for complacency in dealing with a transactional president.

As more-weighty US allies are likely to find at the NATO summit, Trump is mightily reluctant to help those who don’t pull their weight, and that will apply even to “family” like Britain, Canada and Australia.

And who can blame him? Along with Britain and France, in a much more circumscribed way, America has been the world’s policeman: the guarantor of a modicum of restraint from the world’s despots and fanatics.

No other country has had both the strength and the goodwill for this essential task.

And its thanks for seven decades of watchfulness and prodigious expenditure of blood and treasure, has been arch-condescension from the intellectuals whose freedom America has protected; and commercial exploitation from the competitors that the American-led global order has created.

It’s little wonder that Trump wants trade that’s fair as well as free and it’s little wonder that he’s tired of so-called allies who give sermons from the sidelines while America keeps them safe.

The truth is that the rest of the world needs America much more than America needs us.

America has no threatening neighbours. It’s about as remote from the world’s trouble spots as it’s possible to be. It’s richly endowed with resources, including – again – energy. Its agricultural capacity is almost boundless. Its technology is second to none. Its manufacturing base is vast. Its people are entrepreneurial in their bones. From diversity, it has indeed built unity and an enviable pride in country.

In many respects, it’s the world in one country, only a better world than most of that outside. An America living in splendid isolation from troubles across the sea might lose little, and perhaps gain much, at least in the beginning. A fortress America would be as impregnable as any country could be.

In the relatively peaceful world that America has policed, and in the trading environment that America has shaped – thanks also to the limited economic freedom that the communists have allowed – the Chinese have dragged close to half a billion people from the third world to the middle class in scarcely a generation.

It’s the biggest and quickest advance in human well-being in all history, facilitated by American benevolence, so that the Chinese economy now rivals America’s and their power soon will.

Compared with their communist cousins in the old Soviet Union, the Chinese seem less ideological and more nationalistic; more interested in trade and investment ties than military ones; whose global ambitions are more economic than strategic, at least for now.

In “America First” mindset might conclude that China should be left alone, even to oppress others, provided it doesn’t bother the US.

Still, for Trump, “America First” doesn’t mean “Only America” yet: or “you’re on your own, world”. America hasn’t lost its pride, its values or even its sense of “manifest destiny”; it’s just that it’s weary of “pay(ing) any price, bear(ing) any burden….(or) support(ing) any friend….to assure the survival and success of liberty” (in JFK’s stirring words) on behalf of countries that aren’t equally committed.

Trump is clearly impatient with the liberal internationalism that has shaped American policy for seventy years because he worries that it’s been much better for others than it has been for America.

America has disproportionately shouldered the burdens. Others have disproportionately gained the benefits, so enough is enough and there will be no more one-sided alliances.

There are two possible versions of the Trump doctrine that’s evolving: one goes something like this: America might help those who help themselves, but will be more likely to help those who help America. A kinder version might be: they’re your values too, so don’t expect us to be the only ones fighting for them.

President Obama spoke beautifully about American values but was always cautious and sometimes slow to stand up for them. On his watch, the rules based order was already unravelling.

Trump is much more honest about the limits of American power. For all the former president’s out-spoken high-mindedness on fringe issues like climate change, Trump’s America is more robust than Obama’s.

It’s certainly less apologetic and still ready to use force, so at least for those allies that don’t shirk their responsibilities, Trump’s America should remain a reliable partner. Just don’t expect too much.

A new age is coming. The legions are going home. American values can be relied upon but American help less so. This need not presage a darker time, like Rome’s withdrawal from Britain, but more will be required of the world’s other free countries. Will they step up? That’s the test.

For the threat of Islamism hasn’t diminished. Iran is an Islamist state (albeit of the Shiite variety) trying to get nuclear weapons.

Over the past 50 years, each manifestation of Islamist terrorism, from the PLO to al Qaeda to Daesh has been worse than the one before. Hence, the eclipse of Daesh is almost certainly just the current calm before the next and worse storm.

Until Islam is wholly purged of its “death to the infidel” mindset, ramifying war and random violence are ever-present probabilities.

Then there’s Russia that’s clearly become a predatory state.

Under Putin, Russia has invaded the Ukraine, meddled in Syria, coerced Georgia, had numerous domestic critics murdered, and killed opponents of the regime abroad. Putin’s Russia is the only big country in Europe in the last three quarters of a century, to have waged aggressive war against its neighbours.

For Australia, Putin will always have blood on his hands due to the Russian missile battery that shot down MH17 killing 38 Australians among 298 innocent travellers.

China is still an economic opportunity but it’s a big strategic competitor too. With the militarisation of the South China Sea; the bullying of the Philippines, Vietnam and even Japan; probing against India; and the ever-present danger to Taiwan, it’s asserting itself all around the region.

It’s still a “dictatorship of the proletariat”, now with a president-for-life.

Some of China’s swagger is the natural heft of a very large country, re-invigorated by economic success. But China’s goodwill often seems conditional: on shunning the Dalai Lama, ignoring the slow squeeze on Hong Kong, abandoning Taiwan, and ultimately on choosing China over America.

These are not choices that any free country should have to make in order to be China’s friend.

So far, the rise and rise of China has been good for the wider world, as well as for its own people. It’s been powered, in part, by Australian coal, gas and iron ore for which they’ve paid us well. High quality and inexpensive Chinese goods have also sustained our standard our living.

For Australia, China is not only our biggest market and an increasingly important foreign investor; most years, it’s our biggest source of foreign students, overseas visitors, and even permanent migrants.

There are now about a million Australians of Chinese background, close to 5 per cent of our population, nearly all of them well integrated into the life of our country, and thoroughly steeped in Australian values. May they never have to choose between their country and their ancestry.

Australia won’t gratuitously offend China but mustn’t be submissive either. Our companies and our universities should not change what they do at China’s behest.

Our foreign policy should not bend in China’s favour – and so far it mostly hasn’t. Indeed, in changing the rules of the Asia Infrastructure Investment Bank to accommodate Australia’s governance concerns, the reverse may even have been true!

While keen to deepen the economic relationship through the free trade deal – China’s first with a G20 country – and to engage culturally in the hope of finding more common ground, my government was always quite clear about the priority of our strategic partnership with America.

“You don’t make new friends by losing old ones” was how I put it.

When President Obama declared at West Point that America could not be the world’s policeman on its own, I said as prime minister, that America need never be alone; and that while America would have more important and occasionally more useful allies, it would never have a more dependable one than Australia.

As PM, I wanted to be a welcome change from those visitors to the White House seeking what America could do for them; offering instead what we could do for America.

When the Wikileaks spying scandal broke, there was nothing but strong public and even stronger private support from Australia. When Daesh stormed across eastern Syria and northern Iraq to the gates of Baghdad, Australian Special Forces, military training teams and strike fighters were there almost as quickly as American because America should never have to fight the world’s fight solo.

Being America’s partner, as well as its friend, will be even more important now, given Trump’s obsession with reciprocity. Indeed, it may be the only hope of keeping America engaged in troubles that aren’t already its own.

In my judgment, Australia should have upgraded its Iraq mission to “advise, assist and accompany” as soon as America did, and extended it into Syria. Australia should have mounted freedom of navigation operations in the South China Sea. And Australia should not only have welcomed moving the US embassy to Jerusalem but shown solidarity with the United States and Israel, the only liberal democracy in the Middle East, by moving ours too.

For the first extended period in Australia’s settled existence, the strongest power in our part of the world is unlikely to share our values.

The rise of China means that we can no longer take for granted a benign strategic environment. We can no longer be sure that someone else will be the first to respond to any challenge to peace, stability and decency in our region.

The expedition to East Timor that Australia initiated and led is unlikely to be the last occasion when strategic leadership is required of us – and all this has seismic implications for Australian policy and for our armed forces.

The defence white paper that my government commissioned said that Australia’s armed forces should be able successfully to defend our country from any likely aggressor, intervene effectively in a regional conflict, and contribute meaningfully to our allies’ military operations around the globe.

China’s rapidly growing military strength as well as the increasing capabilities of other regional countries will inevitably make it much harder to do that than the white paper anticipated.

I fear there will have to be a much greater focus on strategic deterrence, especially if a rogue state like North Korea has long range nuclear weapons and especially if the American nuclear shield becomes less reliable.

For Australia, obtaining the capacity to shoot down incoming missiles could easily become a multi-billion dollar necessity. Almost certainly, our navy will need routinely to be enlarged and strengthened.

There will almost certainly have to be more of our planes rotating constantly through the Butterworth air base in Malaysia. Our ships and submarines might need to spend more time operating from Singapore if they are more readily to be where they could be needed.

Inevitably, our capacity for cyber-defence and cyber-offence and our intelligence gathering will need constant upgrading.

Our too-intermittent relationship with India needs to intensify and its security dimension needs to develop. Especially while we still have much to offer, we should try to make ourselves even more useful to Indonesia. And none of this should mean any withdrawal from the Middle East which is still the most immediate danger to the world’s peace and stability.

My government increased Australia’s defence spending from a historic low of 1.6 per cent to 2 per cent of GDP. I made the commitment to a continuous build of major surface ships and began the process of acquiring new submarines.

To its credit, the Turnbull government has continued and developed this work but I fear that dramatically increased military spending in our region – up 60 per cent in just the last decade – means that rather more now needs to be done.

Can our ships be expected to operate, for instance, without the air cover that an over-stretched America may no longer provide? Can we afford to wait at least 15 years before just the first of the next generation of submarines becomes operational – and does it really make sense to take a French nuclear submarine and re-design it for conventional power to be less potent than it currently is?

My instinct is that acquiring a capacity to strike harder and further and the need to give our country and our armed forces greater protection could soon require military spending well beyond two per cent of GDP. We need to work out what we reasonably require to keep Australia safe, and pay for it, rather than ask what we can get for any particular quantum of spending.

Our armed forces need to be more capable of operating independently against even a substantial adversary because that is what a truly sovereign nation must be prepared to do.

When America spends 3 per cent plus of the world’s biggest GDP on its armed forces – and the rest of the Western world scarcely 2 per cent, it’s hard to dispute Trump’s view that most of us have been keeping safe on the cheap.

America can’t be expected to fight harder for its Australian ally than we would be prepared to fight for ourselves; or to do more for Australia than we are ready to do for ourselves.

John Curtin’s famous plea to America in the darkest days of World War Two actually exposed our engrained tendency to look to someone else for our own protection.

When you think of it, what Trump is making clear – to us and to others – is what should always have been screamingly obvious: that our nation’s safety now rests in our own hands, far more than in anyone else’s.