The denuclearization agreement signed by US President Donald Trump and North Korean leader Kim Jong-un -- despite criticisms that it lacks details and a timeline -- has many implications besides the start of work to remove nukes from the hands of a young dictator who once threatened a nuclear strike on the world’s most powerful country.

Most of all, the historic accord that calls for the formation of relations between the two countries and establishment of a “lasting and stable” peace regime also means the work to dismantle the last legacy of the Cold War has started.

Three major players -- Trump, Kim and South Korean President Moon Jae-in, who brokered the Singapore summit -- are all credited for the mega shift of the situation that once stoked fears of war over the North Korean nuclear crisis.

One thing that went wrong is Trump’s bombshell statement that the US will be stopping South Korea-US joint military exercises, citing its provocativeness and the “tremendous expense” spent by the US military. That is further evidence that Trump is prioritizing his notorious “America First” policy even when working with a close ally on such a crucial security issue.

On his part, it has yet to be seen whether Kim will fulfill his commitment to denuclearization, but there have been signs he may follow a diverging path from his predecessors. Indeed, the Swiss-educated Kim is different from his grandfather and father in many respects, not least in the way he interacts with the outside world.

Of course, Kim’s primary concern is securing security assurance for his dynastic regime and international recognition of his country as a normal state. He wants to be seen -- as Trump said -- as a smart, talented leader, not the young, ruthless dictator of the world’s most isolated country.

The Singapore summit was a good stage for his such endeavors. Whatever Kim said and did -- including his talk, lunch and walk with the leader of the world’s most powerful country -- put Kim into the global spotlight.

Such a scene would have been unimaginable for his grandfather and the North’s founding president Kim Il-sung and father Kim Jong-il. Secrecy and seclusion were the norm during the senior Kims’ days: They rarely traveled beyond their communist allies of the former Soviet Union and China.

Kim’s accommodation of openness is clear in the economy. Since taking power in 2011 after the death of his father, Kim has adopted elements of a market economy, including incentives and special economic zones. One of his top priorities is to develop the North Korean economy, whose gross domestic product remained at $31 billion in 2016, ranking No. 113 in the world, compared to the South’s $1.54 trillion, for No. 11 in the world.

It was against this backdrop that during his recent visit to China he expressed his desire to learn the reform and openness policy of China, which was initiated by Deng Xiaoping 40 years ago. While touring landmark sites in Singapore on the eve of the meeting with Trump, he also said his country wanted to learn about the social and economic development of the city-state.

So is the Kim who the world saw in Singapore different from his grandfather and father who built up a totalitarian state? Has he changed from a man who once stoked fears of a nuclear war, ordered the brutal executions of senior officials, including a close relative, and the assassination of his half brother?

Kim said in talks with Trump that he could come to Singapore “by overcoming wrong prejudices and practices that had been covering our eyes and ears” and that “the world will see a great change.”

The world will get to know whether he is sincere about his commitment to change through follow-up denuclearization talks. The changes, of course, should include real improvements in inter-Korean relations and the North’s human rights conditions.