WHEN, in a hissy fit, North Korea shut down the Kaesong industrial zone almost three years ago, pulling out its workers and expelling their South Korean managers, many were puzzled as to why the conservative administration of Park Geun-hye, South Korea’s president, would work so hard to restart it. A product of the “sunshine policy” of her left-leaning predecessors, the factories just north of the border kept alive a few of South Korea’s twilight industries, producing low-grade shoes and clothes with subsidies from the South and cheap labour from the North.

The joint zone opened again five months later, after seven rounds of talks. But on February 10th it was South Korea’s turn to pull the plug on the complex, for the first time since it opened in 2004. Ms Park announced a complete suspension of operations. Few expect it to reopen during her presidency, which ends in December 2017. The North swiftly cut hotlines, expelled businesses and put its army in charge of the area. The last real point of contact between the two Koreas is no more.

If earlier efforts to save Kaesong tried to show Ms Park’s “trustpolitik” at work—a mixture of carrot and stick to try to get North Korea to engage with South Korea—the zone’s closure suggests that this policy has been ditched. Those dismayed by the move point out that the deal in 2013 involved a pledge to shield Kaesong from lurches in inter-Korean relations. But Ms Park is no longer in the mood for appeasement. In a notable speech to the National Assembly in Seoul, she did not mince words: it had become “indisputably clear”, she said, “that the existing approach and good intentions” would “only lead to the enhancement of the North’s nuclear capabilities” under Kim Jong Un.

The tests of a nuclear bomb on January 6th and a long-range missile a month later were the last straw. Since Kaesong opened, the North has conducted four nuclear tests and five long-range rocket launches. The hard currency that flowed into Kaesong from the South went straight to the state, which returned as little as a fifth to the 54,000 North Korean workers there. The flow amounted to about $130m a year—not much by South Korean standards, but a fortune for the North and enough to help underwrite its nuclear dabbling.

A harder line towards the North is only one change in Ms Park’s foreign-policy outlook. Another is disappointment with China, North Korea’s only friend, largest trading partner and principal donor. It is just possible that China is now getting tougher on the North. In a recent editorial, China Daily, a state-controlled newspaper, said that new UN sanctions, currently being drafted, “must truly bite”. Yet China is unlikely to want to do anything to rock Mr Kim’s regime, for fear of the instability that might ensue. It has responded to the tests with studious restraint.

That is a blow for Ms Park, who had worked hard to woo Xi Jinping, China’s president. The two have met half a dozen times. Ms Park attended a Chinese military parade in September, the only leader of an Asian democracy to do so (much to America’s irritation). Yet Mr Xi did not take a call from Ms Park for over a month after the North detonated its bomb. Downplaying the North’s tests, says Evan Medeiros, formerly a member of Barack Obama’s National Security Council, has been Mr Xi’s weakest foreign-policy step. Among other things, it has hastened South Korea’s rapprochement with Japan after a protracted spat over history. And now Ms Park has agreed to adopt an American advanced missile-defence system that China has long agitated against.

So shutting Kaesong was probably also a show of determination put on for the United States. Military drills that take place annually in the spring between the two countries are planned to be among the biggest yet. And South Korea, America and Japan are likely to become more public about their three-way co-ordination against the North Korean threat. South Korea is recalibrating its foreign policy: unambiguously hugging its American ally and mending ties with Japan as those with China fray. Ms Park’s legacy may yet be made in the dusk of her presidency.