We're not choosing; we're hoping - hoping that the US will help us. Our providing support to it goes without saying.

If anyone has a choice, it's the Americans. They can choose whether to work at protecting Australia and other countries on this side of the world by resisting China's expansion. Or they can try to do a deal with Beijing, draw a line down the middle of the Pacific and withdraw to the east of it.

Any number of commentators, interviewers, news reporters and pub experts assume that Australia can be a spectator in what they call a competition between the US and China. But we have vastly more at stake in this than the Americans have.

It isn't the US that's less than 3000 kilometres from the nearest Chinese military base, nor is it the US that has seen Chinese forces move 1000 kilometres closer over the past decade with island building in the South China Sea. Rather, that's our deeply disturbing problem.

Nor is the US outmatched by the Chinese economy 11 times over, as we are. And Washington hardly needs to worry that Canada and Mexico might turn into vassals of Beijing, whereas our strategic nightmare is that an unrestrained China will gain military access to the territory of our neighbours in the islands north of us.

That's just what could follow from China's objective of seizing control of Taiwan, which it aims to achieve by threat and intimidation if possible or a shocking war if necessary.

With the exceptions of Japan and Taiwan, east Asian countries are already looking at China like bunnies in the headlights. They hope Washington will keep the region stable but think they must be on good terms with Beijing in case it becomes dominant.

If the US tries and fails to defend Taiwan against Chinese attack, or if it doesn't even try, those countries, to varying degrees, will have to become Beijing's obedient servants. What else could they do?

We should consider what we would do if China could then extend its military perimeter to the islands to our north and if the US had pulled back to its side of the Pacific, leaving us alone.

In fact, there are military strategies we could use, but at best it would be a terrifying, hanging-on-by-the-fingernails situation.

The government of the day could decide that our best option would be what it might call "accommodation" with the Chinese Communist Party, which in practice would mean accepting as much control over our affairs as the party demanded. Picture the Australian government conducting policy according to China's interests and at the direction of a Chinese embassy that had been expanded into a sort of parallel administration.

No, that's not wildly imaginative speculation; it's worryingly plausible. We never see a limit to the CCP's desire for control of anything that it regards as potentially useful or harmful. The party is always after whatever power it can get.

Note the simple sequence of steps that gets us to that point: loss of Taiwan, east Asian diplomatic collapse, then Chinese forces on our doorstep.

So the key is protecting Taiwan, an island that probably not one in 200 Australians has visited and not one in 20 has thought about for more than 30 minutes.

Thank God that the US, finally, is fully aware of the challenge in defending Taiwan and is working hard at preparations. Thank God that the US has finally realised that as far as possible China must be restrained - diplomatically, militarily, economically and technologically.

Think again about that desperate position we'll be in if Washington changes its mind, if it decides that it can't afford the monetary cost of this effort, doesn't want the risk or war and, in fact, would itself be safe enough even if it let China take control of our side of the world.

Think about it next time you hear or read someone questioning whether we really have any business in this "competition" between the US and China, perhaps someone who piously suggests that we should be above such grubby stuff.

In fact, our task is not to sneer at US efforts but to assist by building up our forces as fast as we can, focus them on the China problem and make our territory available to the Americans.

MORE AGE OF THE DRAGON:

And we had better think about that nightmare Australia-all-alone scenario, too. For that, the most important thing to do now is accelerate our population growth.

US withdrawal from the western Pacific is frighteningly more possible than we acknowledge.

The Republican Party has always had an isolationist element that its traditional leaders have managed to suppress. But that isolationism is growing. More than two-thirds of Republicans now agree with the statement "We should pay less attention to problems overseas and concentrate on problems here at home."

Australia is not in the position of Italy in 1914 at the beginning of World War I, when the government in Rome wondered whether it preferred to back Britain and France on one side or Germany and its charming jackboots on the other - or maybe just sit out and watch the war unfold.

Instead, we are in the position of Czechoslovakia in the mid-1930s, when it desperately hoped Britain and France would stand by it against the neighbouring ogre that was Nazi Germany.

They didn't, by the way. Germany swallowed Czechoslovakia.