While there are some in the United States saying it will win their leader a Nobel Peace Prize, doubts have been cast on whether the planned summit in Singapore between US President Donald Trump and Democratic People's Republic of Korea leader Kim Jong-un will actually take place.

The on-off-on roller-coaster has exposed a shocking lack of seriousness and preparedness on the US side, particularly on Trump's part, as to how to seize such a rare opportunity to ease the tensions on the Korean Peninsula.

It is true that for the two countries to agree to the historic meeting is in itself a major breakthrough, especially if we recall the saber-rattling and war of words just months ago.

But while the DPRK has made goodwill gestures in the past weeks toward improving relations and denuclearization, by blowing up its nuclear test site and releasing three US detainees, it is unclear what concessions the US is willing or able to make going to the summit and subsequent talks.

Pyongyang has made it clear that it will cancel the summit if Washington forces it to unilaterally surrender its nuclear weapons program or continues to float the Libya model.

The DPRK has long cited security concerns to justify its nuclear program. After all, a peace treaty to end the Korean War, which started in 1950, has yet to be signed by the relevant parties.

The US security guarantee must be in a formal document so that the Trump administration and future US leaders will be obliged to abide by it.

It is a lesson learned from the Libya disarmament in 2003. The Barack Obama administration and its NATO allies pursued regime change in Libya in 2011, eight years after Muammar Gadhafi gave up his nuclear weapons program.

In this sense, the US has much to do to make its security guarantee credible this time around.

The US likes to blame the DPRK for all the past failures on denuclearization. But certain US government actions－such as when the US government stopped shipping oil to the DPRK as agreed upon and former president George W. Bush calling Pyongyang part of an "axis of evil"－were much to blame for past setbacks.

Key in the security assurance is the DPRK's long-standing opposition to the massive US troops stationed in the Republic of Korea and their frequent joint drills on and in the waters off the peninsula.

If a peace treaty to end the Korean War is signed, it does not make sense for the US to continue to deploy those troops on the peninsula. Holding regular military exercises aimed at the DPRK would become unnecessary provocations.

Many US politicians and the military-industrial complex do not want to see a de-escalation of tensions on the peninsula, let alone a unified Korea, because that would take away the justification for such a US military presence there.

The phasing out of UN sanctions and US unilateral economic sanctions on the DPRK, while a reasonable expectation for the DPRK, will unfortunately be extremely challenging politically at home for Trump. China has long advocated direct contact between the DPRK and the US to ease tensions. China does not oppose Korean reunification because no one else in today's world better understands the term "reunification" than Koreans and Chinese.

The Chinese would applaud a reunified Korea as a peaceful, prosperous and friendly neighbor. But China would not like to see a reunified Korea that becomes a US puppet and is used as a geopolitical tool by the US against China.

The ball is now in Trump's court.

The author is deputy editor of China Daily USA.