His arrival was delayed by a maintenance issue with the secretary of state’s aging plane, and he found himself forced to overnight in Tokyo. He is to arrive here Saturday, under the current plan, just as many in Beijing are streaming out for a weeklong national holiday. His host, President Xi Jinping, is consumed by the country’s 19th Communist Party congress, which starts Oct. 18 and is seen as the moment for him to further consolidate his power.
Mr. Xi is clearly as worried about the North Koreans disrupting the party congress as the United States. There are rumors of new missile tests, though it seems highly unlikely that the North is yet prepared to attempt an atmospheric nuclear blast, which would be the first in 37 years by any nation. The specter of the North setting off a potential environmental disaster would at a minimum embarrass Mr. Xi, and perhaps force his hand to invoke sanctions that could destabilize the regime, a step China has always refused to take.
“Xi doesn’t want any distractions,” Michael J. Green, a former senior American diplomat who now teaches about East Asia at Georgetown University, said at a forum at the Center for Strategic and International Studies on Tuesday. “Particularly from the North Koreans.”
So in recent days the Chinese have done just enough to hold Mr. Tillerson off for a number of months. They have announced a series of new financial rules that, after the letter of the latest round of United Nations sanctions, should make it all but impossible for Chinese financial institutions to do business with North Korea, at least in any visible way.
North Korean officials recently set up a committee to investigate the impact of the sanctions on the country’s economy and the well-being of the population. The committee’s work was designed to draw international sympathy by highlighting the suffering of North Korean children, women and elderly people, analysts said.
The sanctions are “a brutal criminal act that indiscriminately infringes upon the right to existence of the peaceful civilians,” said a spokesman of the Sanctions Damages Investigation Committee in a statement carried by the North’s official Korean Central News Agency on Friday. “The colossal amount of damage caused by these sanctions to the development of our state and the people’s livelihood is beyond anyone’s calculation.”
On Thursday, the Chinese commerce ministry said North Korean ventures and joint ventures in China had to close within 120 days of the Sept. 11 approval of the latest Security Council sanctions. Some energy supplies have been cut, though the Chinese managed to kill a much tougher American proposal at the United Nations to cut off all crude oil to the North, and allow shipping in and out of the country to be inspected by force, if necessary.
“China has taken some great strides in recent weeks, and we look forward to China adhering to the U.N. Security Council resolutions and fully implementing all those resolutions,” Heather Nauert, the State Department spokeswoman, told reporters on Thursday. “I think the secretary will be thanking them for the steps that they’ve taken in that direction.”
But when not speaking for attribution, virtually no American officials — including Trump administration appointees and diplomats who have dealt with North Korea in the past — believe that any escalation of sanctions will do more than temporarily slow the nuclear program.
“They have no intention of giving it up,” Sue Mi Terry, a former North Korea analyst for the C.I.A. and now a consultant on Korea issues for BowerGroupAsia, said earlier this week in Washington. But it is an exercise both the United States and China must go through, she said, until the United States decides whether it is simply going to live with North Korea’s status as a nuclear state whose weapons can reach American shores.
Mr. Trump insists he will never live with that threat, and says that is what separates him from the past four American presidents. He promises to “solve” the North Korean problem once and for all, after being left “a mess” by his predecessors.
But, apart from his martial sounding tweets and his assurances that the military is prepared to destroy North Korea at his command, he is staying vague about what a solution looks like. One senior aide said recently that in internal debates, there is an assumption that the problem cannot be solved with Mr. Kim still in power, but acknowledged that the United States has no understanding of whether a successor would be better or worse.
For his part, Mr. Tillerson, though hired for his ability to strike deals, has never talked about what the United States would give North Korea in return. There is speculation about a quiet agreement with the North to scale back military exercises. It is doubtful that alone would impress Mr. Kim as he nears the completion of his national mission, a weapon that can reach the United States.
But doing so would require some channel of communication, overt or covert. Asked earlier this week about whether there were any contacts with the North, General McMaster said no, then quickly left the door open to doing exactly that.
“When we do,” he said, “hopefully it will not make it into The New York Times.”
Chinese officials keep discussing a so-called freeze for freeze, in which Mr. Kim gives up nuclear and missile tests and the United States gives up its exercises. But both Mr. Tillerson and General McMaster have rejected that step, arguing that to do it now, with the North’s weapons and delivery systems so advanced, would be to acknowledge the North as a nuclear power, even if there was vague talk of eventually reaching an accord over the ultimate status of the North’s weapons.
Lurking beneath that conversation is another that the United States has consistently tried, and failed, to engage in with the Chinese: a secret discussion over how to plan for a collapse of the North Korean government, when there may be only hours, or days, to scramble for control of the country’s well-hidden nuclear arsenal.
It is a topic the Chinese do not want to discuss and have always avoided, for fear news of the discussion would leak, and it would look as if Beijing were plotting either to abandon or take over the North. Now, some senior American officials say, the subject can no longer be avoided, because if a conflict breaks out, there will be no time to discuss it later.