Since Kim Jong-un has been in power in North Korea, the tempo of the testing of nuclear weapons has only increased. Credit:AP The threat of war, even nuclear war, seems conceivable. The view of North Korea from Washington is diabolically conflicted. Kim Jong-un's regime is seen as both fearsome and farcical, according to analysis by private intelligence outfit Stratfor. North Korea is a throwback to the Cold War, with an obsolete military that the United States could obliterate at will, but one that could nonetheless wreak bloody havoc before its defeat. Soon, if left unchecked, it will have a missile capable of delivering a nuclear warhead to the United States. Or to Australia for that matter.

North Korea prepares to celebrate Saturday's anniversary of the birthday of its founder and Kim Jong-un's grandfather, Kim Il-sung. Credit:AP Historically the world has only been able to influence North Korea to the extent that it can influence China, upon which North Korea depends for the funds that keeps the regime in place and the food that keeps the population fed. In November last year, around the time Barack Obama and Donald Trump were captured together in awkward photographs at the White House, the outgoing President warned the incoming one that his first great foreign policy test would be on the Korean peninsula. An American soldier stands guard during the US-South Korea joint exercise in Pohang, South Korea, last Tuesday. Credit:AP To much of America's foreign policy establishment, the horror of the prospect of conflict was compounded by not only the brashness of North Korea's new leader, Kim Jong-un, but by their lack of faith in their own new President.

In August last year dozens of former Republican national security officials, many of them former top aides or cabinet members for President George W. Bush, signed and published a letter saying they would not vote for Trump. Illustration: Richard Giliberto Today, the world watches on as Trump's "powerful armada", led by the aircraft carrier USS Carl Vinson – and joined by Japanese warships – steams into the region and North Korea prepares to celebrate Saturday's anniversary of the birthday of its founder and the leader's grandfather, Kim Il-sung. It is the sort of anniversary that the regime has traditionally celebrated with an explosive act of defiance, like a missile or nuclear weapons test. Japan's Prime Minister has raised the prospect of a chemical weapons test, while South Korea has vowed to "mercilessly retaliate" against any aggression.

Earlier this year China's Foreign Minister Wang Yi likened the US and North Korea to two accelerating trains heading for collision. Kim has declared North Korea is in the final stages of developing an intercontinental missile. Trump has vowed – via Twitter – that this "will not happen". How did it come to this? As Obama suggested in November, this crisis has been a long time coming. The war that began in 1950, when North Korean invaded South Korea and the US and its allies including Australia, on behalf of the United Nations, stepped in to defend the South, ended with an armistice rather than a formal peace treaty. Technically the war never ended.

As South Korea rapidly industrialised and engaged with the western world, North Korea became a pariah, almost entirely dependent on China (which had taken its side in the war) and devoted itself to building its military capacity. In 1985 North Korea ratified the Nuclear Non-Proliferation treaty and the following year it opened its first test reactor. Ever since, it has pursued not only nuclear weapons but the capacity to launch them. In 2003 it withdrew from the non-proliferation treaty and in 2006 held its first underground test of a nuclear weapon. Though at times over the years the regime has been persuaded to slow its development program, since Kim Jong-un has been in power the tempo of the testing has only increased. Last year it conducted its largest nuclear test and this year it has fired a series of ballistic missiles into the Sea of Japan. In the near future, should it not abandon its program, it will soon develop a missile that puts parts of the US – and Australia – in range.

Trump's decision to fire off a volley of missiles at Syria while sitting down to dinner with the Chinese leader Xi Jinping, might have served only to spur Kim's determination to secure a missile capable of striking the US. It can't have escaped his notice, observes Euan Graham of the Lowy Institute, that if Saddam Hussein or Muammar Gaddafi had such a weapon, they would probably not be dead now. What next? So far the world has responded with sanctions, but with 90 per cent of North Korea's trade going through China, they have been ineffective without China's full co-operation. China's interest in North Korea is conflicted too. It is increasingly frustrated by the unruly behaviour of its client state and its brash new leader. But while it would like to see a nuclear-free Korean peninsula, it does not want the North Korean regime to collapse – it prefers to have a buffer on its border rather than a unified Korea that might tilt towards the west.

It must find a way to prosecute a sanctions regime that applies pressure to the Kim's regime without destroying it. Kim will feel secure from invasion only once he has the capacity to strike the US. And without a significant military career of his own he needs to burnish his authority within his own regime. The US, says Graham, might be able to live with a nuclear North Korea, but not one that can strike its west coast. Much of the international calculation depends on the character of the two nation's leaders. Kim, says Graham, has proved willing to take significant risks, noting the recent brazen murder of his half-brother by agents acting in Kuala Lumpur airport. So far the Trump administration is proving to be difficult to read.

Partly this is because it is so new – the world has yet to learn to read the signals emanating from the White House or the State Department. Trump has constantly changed course on policies he resolutely advocated during the campaign, and his senior staff have been engaged in a very public turf war between the nationalist strategist Steve Bannon and senior advisor, Jared Kushner, a man perceived to be both more outward looking and more temperamentally moderate. The uncertainty has made some observers nervous. Once upon a time analysts and diplomats could read the semaphore coming from Washington. Not any more. The China scholar Robert Daly told Fairfax Media: "On that, I can only resort to interpreting Donald Trump's tweets." But Graham says Trump's unpredictability, combined with the sense he is less cautious than his predecessor, has been useful in this instance. "China has great influence over North Korea. And China will either decide to help us with North Korea, or they won't," he said.

Trump told the Financial Times in an interview in the Oval Office earlier this month. "If China is not going to solve North Korea, we will." Trump's comments had perhaps stirred China to take more serious action to bring North Korea to heel. Those comments came after his Secretary of State, Rex Tillerson, said the period of "strategic patience" – which Graham describes as Obama's term for doing nothing – had come to an end. By the end of the week, even as the USS Carl Vinson ploughed towards Korean waters, it seemed Trump's threat to act alone was more likely to refer to sanctions than a military attack. Tillerson had reportedly said in Russia that the US agreed the North Korean situation could only be solved through political means.

The question remained, to what extent would China help? Historically, China has been accused of not wanting to risk instability on its northern border, fearing a flood of refugees, by inflicting economic sanctions that could cripple North Korea. It had used a loophole in UN resolutions that allowed trade classed as aid to be sent to North Korea, if it prevented the civilian population suffering adverse humanitarian consequences. But the mood of Chinese state media and China's North Korea watchers this week has been clear: North Korea's nuclear weapons program and missile launches are not in China's strategic interests, and have to stop. Chinese public sentiment has hardened and will support the Chinese government taking new and tougher sanctions against its rogue neighbour, including cutting Chinese oil supply to North Korea, the Global Times tabloid editorialised this week.

This week the Global Times, which is state-controlled, wrote in its editorial that North Korea had one way out – stop its nuclear program and accept Chinese security protection. The alternatives were the potential for US attack, or to collapse under tougher United Nations sanctions. China's Foreign Ministry has declined to comment on reports that China's nuclear envoy, Wu Dawei, agreed this week with South Korea that tougher sanctions that would be "unendurable" to North Korea will be implemented by China, if passed in the UN Security Council. The US is reported to be pushing for China to crack down on Chinese trading companies that continue to deal with a network of North Korean front companies, allowing the regime to generate income. China cutting off its crude oil pipeline to North Korea, which is classed by China as "aid", has been touted as another potential step by Chinese media. South Korea's Foreign Minister Yun Byung-se told his parliament this week that some of the proposed sanctions had been agreed, but not all.

Was this negotiation – how hard to go on sanctions – the catalyst for Trump's tweet this week that the US would solve the problem without China? China's Foreign Ministry on Thursday said it would not support unilateral sanctions that harmed China's interests. North Korean coal tankers were turned away from Chinese ports this week, after an order from the Chinese government on Friday that Chinese trading companies must reject North Korean coal. The order came after President Xi met in Florida with Trump. It was the latest step by Beijing to show it was finally strictly enforcing UN sanctions imposed in November after North Korea's fifth nuclear test last September. Chinese customs data was released on Thursday which officials said proved Chinese coal imports from North Korea had plunged by half in the first quarter of 2017, after a February ban by Beijing on any more coal imports this year in line with UN sanctions.

The coal import ban followed Kim Jong-un apparently assassinating his half brother in Malaysia, and a North Korean missile launch in February. The next barrage of missiles, fired into the sea off Japan in March as the US and South Korea conducted military drills, prompted the Chinese government to warn the rising tension on the Korean peninsula was dangerous and could lead to conflict. When the US rushed to deploy a controversial missile shield and radar in South Korea, designed to protect the South Korean population from North Korean missiles, but also allegedly capable of spying on Chinese military activity, relations between South Korea and China plunged. Nonetheless, in the wake of the summit between Xi and Trump and a subsequent phone call, China, the US and South Korea appear to be working in concert to curb North Korea. This is not to say that the threat of conflict has entirely abated.

As North Korea moves towards long-range missile capacity, some analysts have speculated that Australia could be targeted, particularly because it lacks a missile defence system. Graham believes this threat might be over estimated given that the North Korean regime has spent years casting the US, Japan and South Korea as its main enemies. Either way, he says, the US would ask Australia, which has already fought in Korea, to contribute should a war break out on the peninsula. Peter Jennings, executive director of the Australian Strategic Policy Institute, believes that if North Korea fires another test missile the US will seek to shoot it down. Such an action would not necessarily precipitate a war, though a first strike on North Korean nuclear facility might, says Jennings. Should that happen, there is a high likelihood of mass casualties. In its recent analysis of a potential war with North Korea, the intelligence consultancy Stratfor predicted that the South Korean capital, Seoul, would be targeted by massed artillery fire from across the border, and suffer significant civilian casualties. Similarly, civilians in North Korea would suffer as those batteries were silenced.

It could also target American bases in South Korea and Japan with its existing stockpile of ballistic missiles, potentially armed with biological, chemical or even nuclear weapons. A subsequent invasion through the demilitarised zone and South Korean minefields would be a bloody affair that would see the North Korean state finally destroyed. The US cannot allow Kim to have his missile; Kim cannot consider himself secure until he does It is, says Stratfor, a problem without a solution.