Soldiers travelling to and from Europe had seen where the choke points at which our links with the rest of the world could be disrupted were. The same was true of the emigrant population; all of whom came by sea.

Now, with Europe 24 hours away by jet and most long distance travel by air, it is easy to forgot the bulk of trade goods still come and go on ships.

This is why it would be much easier for Scott Morrison to explain the government's decision to commit a naval frigate and an observation plane to the US-led task force being formed to protect oil tankers from interference by Iran in the Strait of Hormuz to the voters of Billy Hughes's day than his own.

The news has already been greeted with cries of "all the way with the USA" and "America's lackeys" by the anti-US camp. This ignores the fact Morrison is right in saying this is a national security issue and far more complex than just choosing to back our most important ally in a nascent conflict with Iran.

The deepening crisis, as the PM, senior defence personnel and politicians including former Senator Jim Molan have been saying for some time, has the capacity to further destabilise an Australian economy that appears to be moving closer to a technical recession by the day.

"Australia," the US ambassador, Arthur B. Culvahouse Jr, said last week, "gets roughly 10 to 20 per cent of its oil through the Strait of Hormuz".

While that does not seem to be a worryingly significant amount, it needs to be considered in conjunction with other factors. The most telling of these, as Molan has been at pains to stress, is Australia has been in breach of its international obligation to maintain at least 90 days of fuel import reserves since 2012. We are now down to just 55 days, a figure which means that according to the standards set by the International Energy Agency we rank 15^th out of 25 developed nations on fuel security. We are also ranked last in our region on our trade balance in refined fuels.

"There is no point in having 12 fantastic submarines and 75 F-35s if you've got no fuel for them," Molan said. The same is true for civilian trains, planes and automobiles; including the big trucks that bring the food into our largest cities.

While Molan, a former senior allied commander in Iraq, is no dove, he is on the money when he says countries such as Australia can't sit back and expect the US to do all the heavy lifting when it comes to keeping the trade routes open.

Almost 40 years have passed since Ronald Reagan built up a 600 ship navy to take on the Soviets. America's naval strength is now well under half of that.

Given any disruption in shipping through the strait is, as Morrison said, "a potential threat to our economy", it makes a lot of sense for Australia to pitch in.

Economic modelling carried out by ACIL Tasman in 2012 found that even a short closure of the water way, which separates Iran and Oman, would have a significant effect here. This was because the Asian oil refineries on which we then relied for 64 per cent of all our petroleum imports sourced around 70 per cent of their crude oil from the Middle East. Estimated losses in real income from a one week closure of the strait was put at between $2 billion and $3 billion. The longer it dragged on the worse the numbers would get.

This is a classic case of an ounce of prevention being worth a pound of cure.