Following spiralling tensions in 2017 over North Korea’s nuclear weapons and missile programs, the new year has brought unexpected respite. Not only has Pyongyang offered to send a delegation of athletes to the Winter Olympics hosted by South Korea, and the two nations reopened a diplomatic hotline, but the South says the North has agreed to resume high-level bilateral talks this coming week.

So the diplomatic mood in the peninsula in 2018 could become very different from the end of last year. Yet the mini-rapprochement is fragile, and a key question remains: Will it be significant and sustained in the coming weeks in the face of continuing tensions between Pyongyang and Washington?

At the end of 2017, the apparently gathering storm between the US and North Korea was showcased by the latter’s test firing in late November of an intercontinental ballistic missile (ICBM) that was more powerful and flew higher than any yet by Pyongyang. The launch, condemned by US President Donald Trump, who said he “would take care of the situation,” seemingly intensified his 2018 headache over how best to tackle Pyongyang’s provocations.

While Trump has previously said “talk of appeasement with North Korea will not work, they only understand one thing,” he has very cautiously welcomed the prospect of renewed high-level bilateral dialogue between the North and South. Yet his own relationship with North Korean leader Kim Jong Un remains in deep freeze.

This reflects the growing evidence that North Korea is moving closer to developing a nuclear warhead capable of being fitted onto an ICBM that can strike the US mainland, let alone key US allies such as Japan in much closer proximity. The November missile test, which came just a week after Trump declared North Korea a state sponsor of terrorism, travelled some 4,500 km high and landed around 1,000 km from the west coast of Japan.

Strikingly, the US Union of Concerned Scientists has calculated that if the missile had flown on a standard trajectory rather than a lofted one, it would have had a range of 13,000 km, enough to strike Europe, Australia or any part of the continental US.

With the US homeland looking increasingly vulnerable, the Trump team has begun laying the ground in 2018 for a further tightening of the military and diplomatic screws on Pyongyang, especially should the recent warming of relations between North and South Korea break down.

Coinciding with continued sanctions diplomacy at the UN, the US plans further tests of the Terminal High Altitude Area Defense (THAAD) missile system. Condemned by North Korea, China and Russia, THAAD is being deployed by Washington in South Korea as a means to potentially intercept missiles launched by the North.

It remains unclear whether the mini-rapprochement between North and South Korea will prove significant and sustained in the coming weeks.

Andrew Hammond

Recent rhetoric from Trump, including his assertion that he has a bigger and more powerful “nuclear button” than Kim, has increased international concerns that the US president might now be thinking much more seriously about a pre-emptive strike in 2018 on Pyongyang’s nuclear capabilities. Trump has said the North “is behaving in a very dangerous manner, and something will have to be done about it... and probably dealt with rapidly.”

While Washington’s next steps are not crystal clear, and will depend partly on the outcome on the mini-North-South rapprochement, the two-decade-long US policy of “strategic patience” toward Pyongyang is now over, with all options on the table.

Besides military force, which Trump threatened in 2017 with his “fire and fury” and “locked and loaded” rhetoric, potential actions include interdicting ships suspected of selling North Korean weapons abroad, one of the regime’s key sources of income.

But before any significant, hawkish actions are taken, the Trump team will probably want to be seen to “exhaust diplomatic options,” its Ambassador to the UN Nikki Haley said last year. Here it will watch with interest, and skepticism, the new dialogue between North and South.

Going forward, even Trump knows it would be wise to try to bring other parties, especially China, on board for any intensified package of actions. Yet beyond key regional allies such as Tokyo, others — especially Beijing — have so far been reluctant to take too sweeping measures for fear of squeezing Pyongyang too hard.

A key reason China has so far differed from the US regarding the scope and severity of actions against the North is that it does not want to push the regime so hard that it becomes significantly destabilized. From Beijing’s vantage point, this risks Pyongyang behaving even more unpredictably, and the outside possibility of the regime’s implosion.

This may not be in China’s interests for at least two reasons. Firstly, if the Communist regime in the North falls, it could undermine the legitimacy of the Chinese Communist Party. Secondly, Beijing fears that the collapse of order in its neighbor could lead to instability on the North Korea-China border, a potentially large influx of refugees that it would need to manage, and ultimately the potential emergence of a pro-US successor state.

Taken overall, it remains unclear whether the mini-rapprochement between North and South Korea will prove significant and sustained in the coming weeks. With the Trump team skeptical, 2018 could yet see tensions rise again in the peninsula, especially if the warming of North-South ties proves short-lived and Pyongyang conducts further nuclear and missile tests.

• Andrew Hammond is an associate at LSE IDEAS at the London School of Economics.