Nevertheless, while the goal in Singapore was to work towards “the complete denuclearisation of the Korean peninsula” and to build new relations between the two countries, there has been no discernible progress during the past seven months.

One such trade-off might involve the shutdown of fissile fuel production at Yongbyon, under appropriate inspections, in exchange for sanctions relief and/or a preliminary declaration ending the Korean war.

In this regard, Vietnam was not chosen for its location alone but because it offers some intriguing possibilities as a facilitator, if not oversold.

On the one hand, the US and Vietnam have patched up relations since the end of a brutal war 45 years ago and now boast a burgeoning economic and trade relationship as well as the basis for increasing cultural and political exchanges, making it an exemplar for what is achievable.

On the other, the rosy scenario of Pyongyang duplicating Hanoi’s dynamic growth in its trade and economy overlooks the prior track record in North Korean-Chinese economic relations.

Kim’s father, Kim Jong-il, made innumerable trips to China’s economic development zones but little or anything rubbed off in terms of economic development. Like father, like son? We’ll have to wait and see.

At the same time, historical factors provide a more realistic assessment of what might be possible, as well as the potential hurdles, beginning with a shared history as divided cold war states.

For one, the fact that Vietnam’s division ended with the South’s surrender to the North may plausibly be still seen in Pyongyang as the “wished for” end game. (In his day, Kim Il-sung embraced it as a rationale to open a second front.)

However, if the North still harbours such a vision, it is sure to be disappointed. In particular, it would undercut the optimism of newly retired US commander in South Korea, General Vincent Brooks, who is on record as stating that the nuclear testing pause and other signs suggest that Kim Jong-un wants “a different relationship with the United States” and is prepared to give up his nuclear arsenal to that end.

Still, this upbeat point of view contradicts the recent assessment of US intelligence agencies, which believe Pyongyang would not give up the nuclear weapons that it relies on for regime survival. In effect, Trump is negotiating against the advice of his intelligence advisers.

Further, while both the Korean war and the war in Vietnam were primarily civil conflicts, the former has eluded the dispassionate assessment of its origins and historical context to a greater extent than any other post-second-world-war conflict in which the US has been engaged.

Having begun as a civil war between Koreans divided politically, ideologically and territorially, it subsequently devolved into a limited Great Power conflict between ideological and geopolitical adversaries – the US, on one side, and China and the Soviet Union on the other.

For decades after the Korean war ended, Washington continued to regard North Korea as a pariah regime lacking legitimacy. In the longer term, the consequences for US policy have been profound: diplomatic relations were never consummated with Pyongyang, nor was a permanent channel of communications ever established, thus reducing US effectiveness in promoting North-South reconciliation or confronting North Korea over its weapons of mass destruction programme.

The key takeaway today is that the Korean war ended as it began, with Korea divided, a product of the cold war but which has outlasted the latter.

This makes Washington a party to achieving political stability and security on a divided peninsula surrounded by three of the world’s most powerful states – China, Japan and Russia. This, in turn, would entail the construction a post-Korean-war security framework for the peninsula.

It could initially be based on a peace treaty, a peace declaration or some other tangible indication that the Korean war has ended, both a key North Korean demand in exchange for denuclearisation, and a step Washington has been reluctant to embrace, wary of potential follow-on demands for a partial and/or complete troop withdrawal or a revision of the US-South Korean alliance.

John Barry Kotch is a political historian and former US State Department consultant