Diplomatic contacts and maneuvers over the denuclearization of North Korea are taking place at a breathtaking pace. These latest developments will have effects on the upcoming NK-US summit in one way or another.

First, US President Donald Trump’s final decision to withdraw from a nuclear deal with Iran will put further pressure on North Korean leader Kim Jong-un as the two sides prepare for a historic summit over denuclearization.

In relation, Kim’s surprise visit to China this week for a second meeting in about 40 days with President Xi Jinping could be seen as a move to send the message to the US that Pyongyang will not simply give up and concede everything and that the two leaders will stand together against excessive US pressure.

Nevertheless, US officials have not refrained from publicly warning that North Korea should take lessons from the US action on Iran. National security adviser John Bolton said the decision sends “a very clear signal” that the United States will not accept “inadequate deals” with North Korea. Bolton and other officials previously expressed frustration with past agreements Pyongyang did not abide by and the “step-by-step” approach suggested by Kim. Saying that Trump wants “a real deal,” Bolton also cited the 1992 joint North-South denuclearization declaration, which included the elimination of both the front and back end of the nuclear fuel cycle and a ban on uranium enrichment and plutonium reprocessing.

He said there are other things the US will be asking for and that a deal between Trump and Kim should address all those issues.

On his way to Pyongyang for a second trip in about a month, Secretary of State Mike Pompeo also made it clear that the US has no interest in following a step-by-step process, which under past administrations had failed to end the North’s nuclear ambitions.

“We’re not going to relieve sanctions until such time as we achieved our objectives,” he said. “We are not going to do this in small increments, where the world is essentially coerced into relieving economic pressure.

Pompeo said he hopes to establish a “set of conditions” that will give North Korea an opportunity to have a “historic, big change” in its security relationship with the US, and achieve the US goal of a complete, verifiable and irreversible denuclearization of North Korea.

All will not go easily in the US terms, however. Kim’s surprise visit to Dalian where he met Xi, was one case in point.

In the meeting coming about two weeks before President Moon Jae-in meets Trump in Washington, the two leaders tried to showcase their seamless joint stance.

Both leaders praised their blood-forged alliance, which refers to the Chinese People’s Liberation Army’s participation in the Korean War. Kim went on to say that the two countries are inseparable. Xi stressed the “political resolution” of the nuclear issue, standing behind Kim’s call for gradual denuclearization.

Now there are no signs of a strain in their relations, which had hit a low in the wake of Beijing’s participation in UN-led sanctions against the North.

It is easy to imagine why Kim and Xi, who had their first-ever meeting just 40 days ago, got together again and had cameras capture their intimate walk together along the beach of the Chinese city.

They were saying in union they will stay together if the US makes what they see as excessive demands. Both Kim and Xi are using their alliance as a card to play against the US.

The Chinese terms for a political solution are different from those for the US and South Korea, which is why Trump and Moon should make sure North Korea is not allowed to seek to avoid complete denuclearization on the strength of support from China.

It was good news that the North allowed Pompeo to take home the three American citizens who were detained in North Korea. But such moves would be mere publicity stunts for both unless they strike an effective denuclearization deal in their summit.