NORTH KOREA sent its latest satellite into orbit on February 7th, five days after Groundhog Day. Much of the world could be forgiven for thinking that, like the protagonist in the 1993 film of that name, they are stuck in a time loop. They wake up, North Korea tests a nuclear weapon, other countries condemn its actions and the UN Security Council descends into bickering until the cycle begins again. But just as in the film each day is subtly different, so with North Korea now: the latest test may actually mark the end of a period in which China was prepared to get tougher on its unruly client. From now on, China and America may disagree more strongly about how to deal with the nuclear risks that North Korea poses.

In 2012, after Kim Jong Un, the North’s third-generation dictator (pictured above), last tested a satellite, China endorsed a UN resolution that tightened sanctions against his regime and even sounded a warning, via Global Times, a Communist Party newspaper, that if the North “engages in further nuclear tests, China will not hesitate to reduce its assistance”.

Three years on, a Chinese spokeswoman merely expressed “regret” at the new launch, while the foreign minister, Wang Yi, sounded a warning that any UN resolution “should not…destabilise the Korean peninsula”. In contrast to such mildness, South Korea said it would shut down the Kaesong industrial complex that it runs jointly with the North. That is a big step. The factory park just on the north side of the two countries’ border employs 54,000 North Koreans working for dozens of South Korean companies. It is the first time the South has shut the park—previous closures were initiated by the North, when it wanted to apply pressure on the filthy capitalists running the South.

South Korea’s move over Kaesong is an indication of how seriously it takes both the satellite launch, which was really a cover for testing a long-range missile, and the test of a nuclear device, the fourth such, which took place on January 6th.

The three fatties

A change in China’s attitude does not reflect greater friendliness towards the regime in Pyongyang. Leaders are exasperated with Mr Kim. Ordinary Chinese deride him online as “the third fatty”. (The previous two were his grandfather, Kim Il Sung, and his father, Kim Jong Il.) Junior’s insistence on the satellite test made China’s president, Xi Jinping, look ineffectual. Mr Xi had sent a veteran diplomat, Wu Dawei, to Pyongyang, presumably to persuade Mr Kim to postpone or scrap the trial.

All the same, after a period in 2012-14 when Chinese officials engaged in a lively and sometimes public debate about whether North Korea really was a strategic asset, China’s government has reasserted its traditional support for its troublesome neighbour. According to diplomats, Mr Xi took the decision last summer: a domestically stable North, he ruled, was preferable to an unstable one, even if the country is building a nuclear arsenal. China will keep the North afloat.

And so China has done little to shut off the flow of goods to the North. That matters. The $7 billion-odd a year in bilateral trade is nine-tenths of North Korea’s total trade. Nearly half of the North’s food, seven-tenths of its oil and four-fifths of its consumer goods come from China.

China has long feared that upheaval in the North could cause a refugee crisis. But the clinching argument for Mr Xi may have been that he saw relations with the North in the context of deteriorating relations with America. “It is impossible to co-operate fully on the Korean peninsula,” one official told a visiting professor from South Korea, “so long as the United States continues to engage in provocative behaviour in the South China Sea.” It may be doubted who is really being provocative there. But China’s calculation is that North Korea is a buffer between itself and South Korea, a staunch American ally and host to American forces. At a time when China sees itself as a rival in Asia to the United States, that buffer grows more important.

Yet the cost of keeping the buffer may be going up for China. Jonathan Pollack of the Brookings Institution, a think-tank in Washington, DC, sees “tangible changes in the tone and substance” of American policy since North Korea’s satellite and nuclear tests. John Kerry, America’s secretary of state, called the nuclear test “reckless and dangerous…an overt threat”. He demanded more UN sanctions, just as America’s House of Representatives passed a bill to allow America to punish firms from third countries, such as China, if they help the North evade American sanctions.