This week saw leaders around the world trying to remember whether they were meant to take Donald Trump seriously, but not literally, or literally but not seriously, and also wondering if they have a Greg Norman somewhere they could use.

When US president Trump announced early in the week he was going to levy a 25% tariff on steel and a 15% tariff on aluminium imports, he suggested it was in order to protect national security. As with most Trump utterances, it left everyone trying to decipher just what he meant, because the US imports nearly half its steel from four nations – Canada, Brazil, South Korea and Mexico – which are hardly enemies of the US.

Australia spared US steel and aluminium tariffs, Turnbull confirms Read more

Was he doing this to attack China? He did write a series of tweets that suggested trade with China is in his sights, but while China is the biggest producer of steel, it only exports a small percentage of it to the US.

Some of his other tweets suggested that Trump was instead targeting Europe, but again, hitting steel imports was an odd way to go about it – given Europe made it quickly obvious that it would retaliate with tariffs of its own – and the European Union is one of the few economies with enough grunt not to get pushed around by the US.

Then came the suggestion that Trump was using this to negotiate with Canada and Mexico over Nafta – but that was also odd because that shot down his national security reasoning and opened the US up to retaliation under the World Trade Organisation rules (which would be likely anyway, given his national security reasoning was clearly bogus).

And using the threat of increasing tariffs in free-trade negotiations is a weird way to go about things.

The tariffs do hurt the countries that export steel and aluminium to the US, because they force them to charge more for their product, thereby giving American steel companies an advantage, but they also hurt the US.

Tariffs are effectively consumption taxes designed to give local industries an advantage (or at least an equal footing with international competitors), and they work by raising the price of imports. Now that is great for the owners and possibly workers of those industries, but not so good for anyone else who wants to buy those goods, because now they have to pay more.

A tariff on steel and aluminium imports might help create a few extra jobs in the steel industry, but it also increases the price of all things made with steel and aluminium. That leads to job losses in those industries and also reduces the living standards for everyone because suddenly they have to pay more for things like canned goods, beer, and cars.

Trump trade tariffs: what they mean for Australia and what happens next Read more

One study suggested that for every job gained in the steel and aluminium industries, five would be lost elsewhere.

That does not mean all free trade is a win for everyone – and international trade does not occur in a textbook but rather in the real world where governments subsidise and assist industries. But the general rule is that the costs to the economy increase with the size of the tariff and the number of industries affected (and similarly the benefits of lowering them reduce as the tariff gets closer to zero). A 25% tariff on steel is thus a rather hefty whack.

Trump is in effect going to the negotiating table with a massive weapon – a bit like taking a gun to a knife fight. The only problem is he has the gun aimed at his own foot.

And so it wasn’t a total surprise to see Trump back down and exempt Canada and Mexico, and then later give one to Australia. As the trade minister, Steve Ciobo noted this week, our steel exports to the US amount to about 0.8% of the US market and our aluminium exports account for about 1.5% – so exempting Australia makes little difference.

To that end, reports that we have engaged Greg Norman to do some lobbying on our behalf seem eminently sensible. Not because Norman is some master trade negotiator, but because when dealing with Trump, nations always need to realise he is an insecure, ego-driven fool who needs praise for doing the most ordinary of activities, and who sees every discussion and issue through the prism of how it makes him look.

Norman is probably the only Australian Trump has heard of, and the fact that Norman is famous and successful and would be seeking a favour from Trump would appeal to Trump’s vanity.

We could bemoan the fact that America’s electoral college system has selected this vainglorious ignoramus, or we can suck it up and use it to our advantage.

Anyone, anyone? What happened when the US last introduced tariffs Read more

For now it appears his bluster of levelling tariffs for everyone is weakening. Trump clearly believes this the best way to negotiate trade deals – like any good swindler he’ll ignore the costs and talk only of the benefits.

The danger for Australia has always been not from a direct US tariff but should retaliation come from Europe and China. The last thing a small open economy needs is for the large economies of the world to start playing like it is 1930.

For now everyone is trying to work out just what Trump is after – mostly he is after things that he can call a win (even if they are really not). So nations will be thinking of things they give Trump that don’t matter in order for him to claim victory in the negotiation.

Or they can see if Greg Norman is available for hire.