The cancellation of US Secretary of State Mike Pompeo’s visit to North Korea highlighted once again the uncertainty and complexity surrounding the international efforts to neutralize nuclear and missile threats from the North.

What makes it more intricate is that US President Donald Trump behaves as unpredictably as North Korean leader Kim Jong-un, who is notorious for brinkmanship.

That Trump announced the cancellation of what could have been Pompeo’s fourth visit to Pyongyang just a day after the secretary himself announced his plan to go is yet more evidence that you don’t know what either side could do tomorrow.

When Pompeo announced that he planned to visit the North, it raised hopes that the US and the North might achieve a breakthrough in the denuclearization talks, which so far have made little headway. Washington is demanding the North first provide a list of nuclear arsenals and facilities as well as a denuclearization road map, while Pyongyang is insisting that the US first declare an end to the Korean War as a gesture precluding future hostile acts.

Optimism further rose because the announcement followed news reports about a possible visit to Pyongyang by Chinese President Xi Jinping early next month, followed by the third inter-Korean summit between President Moon Jae-in and North Korean leader Kim Jong-un in Pyongyang in the same month.

The most positive scenario was that Trump and Kim, who held a historic meeting in June in Singapore, would meet again in New York on the occasion of the UN General Assembly and strike an accord ending the Korean War.

That hope, however, lasted just one day, as Trump announced the cancellation of the secretary’s visit in a tweet. Trump made it clear that he was postponing the secretary’s visit because denuclearization was not making “sufficient progress.”

That statement indicates that Trump, mired in escalating scandals involving his close associates, did not want Pompeo to return home empty-handed, as that would have inflicted political damage ahead of the midterm elections in November.

In that sense, it is fortunate that the US leader did not -- or was unable to -- seek to settle for a makeshift compromise with the Kim regime, which also needs a political boost ahead of the Sept. 9 anniversary of its founding.

But Trump tied up the North’s denuclearization with another knotty issue facing him -- the trade war with China. It is not the first time that the US leader has accused Beijing, Pyongyang’s sole remaining ally and largest economic benefactor, of not doing its utmost to rein in the North.

This time, Trump said China was “not helping with denuclearization” as it once had, because of his tougher trade policy. He also said Pompeo’s visit to Pyongyang could take place in the near future, but “most likely after our trading relationship with China is resolved.” He is making China a scapegoat for his failure to achieve progress on North Korean denuclearization.

Trump at the same time left open the possibility, tweeting his “warmest regards and respect” to Kim and saying he looked forward to seeing him soon. But this comment too could be taken as a gesture of insistence that the deal he made with Kim in June has not collapsed.

What’s certain is that -- as seen by the cancellation of Pompeo’s visit to Pyongyang -- the US endeavors to achieve a final, fully verified dismantlement of the North’s nuclear capabilities have hit a snag. This means the US may impose additional sanctions against Pyongyang, which was found to have been continuing its nuclear activities.

The situation calls on the South Korean government to be cautious in setting the pace of reconciliation programs with the North. Any hasty moves that are not accompanied by progress on denuclearization could dent the international efforts to maintain diplomatic and economic sanctions against the North.

One good example is the Seoul government’s push to open a joint liaison office in the North Korean border city of Kaesong. The US side has already expressed concern that certain kinds of logistical support for the joint liaison office could violate the UN-led sanctions. The office then could become a source of friction between the South and the US.

That is the last thing that should be allowed to happen.