As President Moon Jae-in aptly described, it will be a historic milestone in the quest for peace on the Korean Peninsula that North Korean leader Kim Jong-un and US President Donald Trump will sit down with each other over the nuclear crisis.

It indeed is a drastic turnaround for the two, who until a few months ago traded threats of military strikes and stoked fears of war, agreed to hold face-to-face talks by May.

The surprise agreement strengthened the momentum for settling the North Korean crisis peacefully that was laid by the agreement of Moon and Kim to hold the first inter-Korean summit in 11 years in late April.

Moon, an advocate of engagement policy toward the North, deserves credit for brokering a historic meeting between the leaders of the two former war adversaries.

There are some who question Kim’s sincerity about denuclearization and what appears to be Trump’s impulsiveness in accepting Kim’s proposal for talks. But what is certain is that the upcoming inter-Korean summit and the unprecedented North Korea-US summit dispelled fears of war, for now, and offered an opportunity to resolve the Korean problem peacefully.

Indeed, the two successive summits raise hopes for resolving the North Korean nuclear issue that has been dogging the international community for a quarter of a century.

Moreover, successful Kim-Trump talks will help establish permanent peace on the Korean Peninsula and facilitate the eventual reunification of the two countries. Indeed, what the two agree or disagree on will heavily affect the Cold War order that has remained on the peninsula for decades.

In contrast, a breakoff of the Kim-Trump talks will deepen the crisis. Some experts, like Victor Cha, Trump’s former nominee for US ambassador to South Korea, already warned that a failed Kim-Trump meeting could bring the two countries to the brink of war.

What’s essential for preventing such a worst-case scenario is to make sure Kim makes a sincere promise to abandon nuclear arsenals and missiles and takes actions for complete, verifiable and irreversible dismantlement of the weapons.

Kim told South Korean envoys who visited Pyongyang that his country has no reason to possess nuclear weapons if there is no hostility and security threat to itself. He also said that it would not test nuclear bombs and missiles during the negotiations.

There is skepticism -- which is well grounded -- that such comments alone could not guarantee that Kim will put a moratorium on all activities related to his nuclear and missile programs. It still is possible for the North, without holding new tests, to try to continue to improve nuclear and missile capabilities.

Besides, there are concerns that Kim may try to make the talks with Moon and Trump an opportunity to get international recognition of its nuclear state status. He may also want to consolidate leadership in his country by engaging the leaders of the South and the US. He could gain politically if he succeeds in drawing international economic assistance to resuscitate its impoverished economy and improve the quality of life of ordinary citizens.

These worries that Kim may have his own objectives are based on past experiences. The North Korean regime -- from the days of Kim’s grandfather Kim Il-sung and father Kim Jong-il -- has a good track record of developing nuclear bombs, promising to abandon them and breaking the promise again.

That is why all the negotiations -- including those for the 1994 Agreed Framework and the six-party talks -- and two rounds of inter-Korean summit talks in 2000 and 2007 have done little to check the North’s nuclear and missile development programs.

This time, it is obvious that the Trump administration’s maximum pressure policy and threats of possible military actions were the major factors for forcing the North to come to talks. There should be no letup in the pressure and sanctions on the North any time before the North takes concrete denuclearization steps.

With the two important summits in the making, the North Korean nuclear crisis -- and the Korean question as a whole -- is entering an untrodden path, which could be either bright or dark depending on the outcomes of the high-level talks. All will depend on what’s on mind of Kim, and we may get to know of it in the next few months.