Why is North Korea so difficult?

That North Korea is one of the most brutal regimes to have emerged from World War II was recently highlighted by the tragic story of US student Otto Warmbier and the bizarre murder of the President's estranged half-brother, with strong circumstantial evidence of the regime's complicity.

There was also the 2014 Report by the UN Commission of Inquiry into North Korea. In the words of its chairman, the distinguished Australian law reformer and former High Court judge Michael Kirby, the regime's methods were "strikingly similar" to the crimes of Nazi Germany - he likened prisons to the concentration camps in which millions of Jews, gypsies and political prisoners were exterminated.

But these facts, appalling as they are, do not justify a war likely to kill tens of thousands of innocent men, women and children. We should have learned this lesson from the Iraq War, when a US-led coalition invaded another brutal regime in a war which cost between 100,000 and one million Iraqi lives, but was never justified by an independent, forensic examination of the claims by President GW Bush, later found to rest on fabricated evidence, that Iraq had weapons of mass destruction which posed an imminent threat to Western nations.

While the US blames the crisis on the regime's commitment to a nuclear defence and the media focuses on its reckless missile tests and intransigence, little attention is given to a proposal by China and Russia, but also supported by Germany and others, for a UN supervised peace in which the North would end tests with a view to phasing out nuclear weapons in exchange for the US ending its own provocative military exercises and phasing out trade sanctions.

But to better understand the North's actions we need to go back to 1958, when the US installed nuclear missiles in South Korea in breach of the Armistice Agreement.

They remained secret until 1974, when then US Army Chief General Creighton Abrams testified to Congress that the US had deployed a "tactical nuclear weapon", the Lance missile, in readiness for a limited nuclear war. It was not, He explained, to defend the South from the North, but for a wider, regional defence. This was in line with the Cold War containment strategy, first proposed by famed US diplomat George F Kennan in 1946.

According to Professor Lee Jae-Bong, an expert on the history of the period at Wonkwang University in South Korea, this left the North with a problem, since both the Soviets and Chinese refused to provide it with a nuclear defence and it could not rely on their support if attacked by the South.

That such an attack was a serious risk has been confirmed by US files released years later and publicised by Chicago University Professor Bruce Cumings, an expert on the Cold War in Asia who, along with other post WW II scholars, sought a more balanced account of US history in the region.

They reveal an ongoing concern that Syngman Rhee, the autocratic South Korean President, would re-ignite the war in an attempt to force the US to help unify the nation under his rule.

The missiles were withdrawn at the end of 1991, after the US and USSR signed the Strategic Arms Reduction Treaty in July of that year to reduce nuclear arsenals by one third. The US has, however, consistently pledged since then that it regards South Korea as "under its nuclear umbrella".

While it is unclear how much this US nuclear presence, together with the military exercises (now held twice yearly and designed to simulate an invasion of the North) has shaped DPRK policy, there is little doubt it would be seen as an existential threat by those who came to power during the period.

This feature, together with US trade embargoes going back to 1950, suggest the regime's provocations are a desperate if reckless attempt, after almost 70 years of exclusion from the community of nations, to force the US to negotiate a peace treaty to end the war.