Our federal election is over but the US-China trade war rolls on. Overnight Donald Trump offered some free advice to Australia on how we should play things from here:

‘I am a protectionist!’, the US President tweeted. ‘I don’t think that the history of Australia could have been what it has been without the great industrial enterprises, the great basic industries, the great factories of Australia. I am not saying something clever when I say that, I am saying something quite obvious!’

What a blowhard, eh? And what would he really know about our country anyway? Except of course that these words are not those of Trump, but of Australia’s longest-serving Prime Minister, Robert Gordon Menzies.

What did Menzies really believe when it comes to trade? Over the last few years there has been an unexpected Menzian renaissance. But at the various book launches, mock radio broadcast events and think tank soirees devoted to the great man there has been a tendency to either ignore his views on trade or attempt to make out that he was a free trader at heart –  albeit a closet one, one held back by political realities and small-minded contemporaries.

This view is flatly wrong and contradicted by Menzies’ own words. ‘Are you a protectionist?’ he once asked rhetorically. ‘Yes, I certainly am. I’m a life-long protectionist if for no other reason than that my father would turn in his grave if I were not. But I am that because I believe in it; I see no future for Australia without it.’

You would be hard pressed to find any Liberal MP who would today agree with the founder of their party.

Why then did Menzies believe this? It was not because he was uninterested or uninformed about economics. The guy was a brilliant scholar, extremely intelligent, and well-read. He knew all about Adam Smith. He was, after all, a Presbyterian Scot. Unlike some modern libertarian-types he had almost certainly even read that famous Glaswegian economist’s works. Menzies was also very familiar with the political debates of the early 20th century where trade policy was front and centre, debates involving people like Alfred Deakin and George Reid in Australia, and Joseph Chamberlain (a surprisingly Trumpian figure) and the young Winston Churchill in the United Kingdom. Indeed, it is impossible to understand Menzies’ views on trade without understanding this pre-World War I era.

Unilateral free trade had been the policy of the United Kingdom from the middle of the 19th century since its champions – John Bright and Richard Cobden – had persuaded the then global superpower to adopt it. The policy had undoubtedly lowered food costs and led to an increase in the choices available to consumers, but it was apparent it had also some serious shortcomings.

While the globally-connected financial elite in London had prospered disproportionately, others in the country had done less well. Wages had been relatively stagnant for a long time. Cheap imported grain had decimated agriculture in Britain and Ireland. Cheap manufacturing imports had flooded in and caused harm to the Mother Country’s great industrial heartland. There had been a relative decline in British economic and military power vis-à-vis new rising strategic competitors – notably imperial Germany, which did not practise free trade.

Australia also brought its own perspective to this debate. In the late 19th century we had begun to see ourselves increasingly as a nation. We aspired to be something more than simply a colony shipping primary produce to a distant imperial capital. As with all nations that come into being, Australia’s founding fathers believed we required our own industrial capacity both for defence and to ensure a greater degree of economic and political independence. Theirs was a very different sense of nationhood than you will find among many of the bunyip aristocracy who inhabit the Qantas chairman’s lounge today.

While the British maintained the status quo, the Great War proved the wisdom of the Australian approach. An island nation could not simply expect to be able to import whatever it needs whenever it needs it. German U-boats unambiguously hammered home the message: free trade is ultimately not cost-free.

There are some obvious parallels with our current age: today an increasingly strong Chinese navy asserts itself in old German colonies in New Guinea and the Pacific; Australian commercial interests race to sign on to Beijing’s Belt and Road infrastructure program in the same way British merchants from a different era sought eagerly to participate in the Berlin-to-Baghdad railway; too many see ourselves, not as our founders did, as a nation, but simply an economy in a global marketplace. There remains a widespread assumption, like in Britain in the 19th century, that a liberal trade policy and greater economic integration must inevitably lead to a more liberal global order.

In retrospect the much-heralded Hawke-Keating-Howard era of the 1980-90s may come to be seen much like this British liberalism of the late 19th century. It is not that our recent leaders were necessarily wrong to act as they did when the US was as economically and militarily dominant as Britain once was. But times are different now. We need an honest reassessment and a prudent restructuring of our trade policy settings. Our trading relationships need to be based on a new realism, with a greater appreciation for our national interest, not utopian dreams.

This of course does not mean that nations should cease to trade with each other at all or that any trade agreements are in and of themselves a bad idea. Menzies certainly did not believe that, as his agreement to the 1957 Japan Australia Commerce Agreement showed.

But this is different to believing that unilateral free trade is some type of beau idéal to be aspired to. It is very different to believing that adopting a liberal trade policy will necessarily lead to a more liberal world. It matters a great deal the type of nation you are trading with. Trade relationships and nations are different and all can change over time. Japan today is very different to the Japan of the 1930s. China is not New Zealand. Nor will trade make it so.

On this point the bumptious New York real estate developer currently in the White House and an urbane Melbourne barrister, who spent more time in the Lodge than any other, would have been in remarkable agreement.