North Korea did not hold a nuclear test over the weekend that some had expected, and its missile test on Sunday fizzled. But more tests and launches appear to be only a matter of time, and the Trump administration has pressed China’s president, Xi Jinping, to use much tougher pressure on its neighbor.

“The era of strategic patience is over,” Vice President Mike Pence said in South Korea on Monday.

“The president and I have a great confidence that China will properly deal with North Korea,” he told reporters, but “if China is unable to deal with North Korea, the United States and our allies will.”

China suspended coal imports from North Korea in February, cutting off a major source of revenue for the North. But China has resisted choking off trade with North Korea, and debate over how to balance Pyongyang, Seoul and Washington has sharpened and become more fractious. Trying to stay friends with all sides is proving perilous.

The Chinese government has fiercely objected to an American antimissile defense system, called the Terminal High Altitude Area Defense, or Thaad, being installed in South Korea, fearing it could be used to spy on China. But some Chinese experts have criticized the surge of anti-South Korean anger unleashed by Beijing as counterproductive.

Global Times, a state-run newspaper that often defends Chinese government policy, cautioned last week that North Korea would face harsher sanctions if it went ahead with another nuclear test. On Monday, the paper redoubled that warning, calling for China to choke off most oil supplies to North Korea if there was another test.

Mr. Shen has gone much further than other scholars in calling for a reset.

“The fundamental interests of China and North Korea are at odds,” he said in his lecture. “China’s fundamental interest lies in achieving a stability on its borders and developing outward. But since North Korea acquired nuclear weapons, that periphery has never been stable, so inevitably Chinese and North Korean interests are at odds.”