The biggest question facing Asia isn't the South China Sea: it is alliances with the USA

The problem is America's politics, and especially the movement led by Donald Trump. Photo: John Shakespeare

The international tribunal's ruling last week that there is "no legal basis" to China's claim to almost all of the South China Sea presents Beijing with a public relations problem. But it doesn't tell us anything we didn't already know about the nature of today's China.

In the words of one of America's most influential policymakers on Asia, Kurt Campbell: "We have no doubt about what kind of power China is," he tells me. "China is a dominating power that seeks advantage."

He's right and, of course, it wouldn't be the first great power to fit this description.

The United States declared itself the hegemon​ of the Western Hemisphere with the Monroe Doctrine in 1823. It intervened at will throughout Central America and South America to enforce its will. It waged wars against Spain and Mexico to take territory.

In essence, America accomplished then what China seeks now – its own sphere of influence.

But statecraft, like just about everything else, is a fashion business. What was justifiable in the 19th century is not in the 21st.

There can be a high price for nations to pay for being out of geopolitical fashion. Just ask Japan.

It might have got away with its colonisation of Korea and parts of China early last century if it had been just a half-century earlier.

Tokyo was baffled at why the world was so cross with it. As it kept pointing out, it was only following the example of the Western colonists.

"The US," says Campbell, "has helped create an operating system in Asia that combines trade, openness, peaceful resolution of disputes, and the rule of law that has been very good for Asia, and particularly China.

"The big question is whether China embraces its 21st-century potential or clings to a 19th-century spheres-of-influence approach."

The number one concern in the region today is not China, it's the US. There are questions about the durability of American power, and it's the first time I've experienced this.

Kurt Campbell, former Pentagon official

But for all the questions about China, Campbell says there is bigger one looming over the Asia-Pacific.

"The No.1 concern in the region today is not China, it's the US. There are questions about the durability of American power, and it's the first time I've experienced this," says Campbell, a senior Pentagon official in the administration of Bill Clinton and the topmost Asia policy official in the State Department when Hillary Clinton was its secretary.

He doesn't think that the US is inherently exhausted; the problem is its politics, and especially the movement led by Donald Trump.

"The US campaign has raised more questions about the US role in the world than at any time since the end of the Vietnam War," says Campbell, who advises the Clinton campaign on foreign policy and could expect a senior post in the event that Hillary should win the November election.

He lists four of them: "The debates now are;
1. Do we believe in alliances?
2. Do we believe in trade?
3. Do we believe in forward deployment?
4. Do we believe in American purpose?"

Republican Donald Trump and Democrat Bernie Sanders both championed protectionism, but it's Trump who's gone to extremes of racism and isolationism.

It was Trump who, point for point, challenged the long-standing US consensus on the first three of Campbell's questions. It was Trump who threatened to dismantle the US alliance system.

Trump said in March that the two big US allies in North East Asia, Japan and South Korea "have to pay us" or "have to protect themselves".

If they wanted to arm themselves with nuclear weapons to do so, that'd be OK too. 

These countries are bulwarks of stability and the US alliances have helped make them so. Apart from anything else, their US alliances have restrained them from greater antagonism to each other.

And the US nuclear umbrella that extends protectively over them, as it does over Australia, means that they haven't had to go nuclear themselves to defend against their nuclear-armed neighbours, China and North Korea.

"I shudder to think what might happen to our alliances and to the stability of the Asia-Pacific if Donald Trump were to become president," Tom Schieffer​, US ambassador to Australia under George W. Bush, told me. "I'm voting for Hillary."

If Trump were to dump America's Japan and Korea alliances, the credibility of Australia's alliance with the US also comes into question. Why?

Because the US maintains big military forces in both Japan and South Korea – this is a vital part of the US system of forward deployment. If these bases close, American ability to project power into the Asia-Pacific falls dramatically.

And, just for the record, Trump's demand that Japan and South Korea pay more for the bases? Tokyo and Seoul already pay for most of the costs of the US bases on their soil, other than the salaries of the American troops there.

Campbell says that the US election has exposed that, while American elites have supported US trade and military engagement with the world, it's turned out to be an establishment veneer concealing a popular vacuum: "Until recently, we've been able to discuss defence and security almost detached from the US domestic political debates. We've taken it for granted, but the American people are raising foundational questions. Someone came up to me recently and said, 'Tell me why we have alliances?'"

If Hillary Clinton wins in November, she will have to start making the case to a sceptical American people. And if Trump wins, he either doesn't know or doesn't care.

The big winners? They'd be China, Russia and North Korea, who would be much freer to use sheer force against their neighbours to get their way.

If so, perhaps the region is about to return to the 19th century, after all.

Peter Hartcher is international editor Sydney Morning Herald