Rex Tillerson on Sunday concluded his first trip to the Asia-Pacific region as US secretary of state, after stop-offs in Japan, South Korea and China. North Korea topped the agenda, given continuing provocations from the regime, and Tillerson warned on Friday that Washington’s policy of “strategic patience” is now over and “all options”, including military action , are on the table. Before Tillerson’s visit, Foreign Minister Wang Yi ( 王毅 ) asserted, in unusually blunt language, that Washington and Pyongyang were on a “head-on collision” course, and warned Tillerson on Saturday that “cool-headedness” was needed. How Kim Jong-un put the US on a collision course with China Beijing’s concern here is not just irresponsibility from North Korea, which launched a further four ballistic missiles earlier this month , but what it asserts is the United States fanning the flames by beginning last week its deployment of the controversial Terminal High Altitude Area Defence (THAAD) anti-missile system in South Korea. Successive US administrations have discovered that security tensions on the Korean peninsula have no easy resolution This comes as the South prepares for a a snap presidential election by May 9, after the country’s Constitutional Court upheld a parliamentary impeachment vote against Park Geun-hye. Beijing vehemently opposes the defence system , which it believes could be used for US espionage on China’s activities, as much as for targeting missiles from North Korea. Wang has therefore called for Seoul and Washington to “cease and desist” on THAAD deployment. Successive US administrations have discovered that security tensions on the Korean peninsula have no easy resolution, and have grappled with the challenge of responding not just to missile launches by Pyongyang, but also its nuclear tests. Tillerson acknowledged on Thursday that “political and diplomatic efforts of the past 20 years to bring North Korea to the point of denuclearisation have failed”. US threat to strike North Korea is ‘aimed at Beijing’s ears’ Last year, president Barack Obama’s team talked tough with Asian allies on unilateral and multilateral sanctions, but found China reluctant to take comprehensive, sweeping measures against its erstwhile ally. This dialogue culminated in November with the UN voting to tighten sanctions in response to Pyongyang’s fifth nuclear test . The reason why China and the US differed last year over the scope and severity of international sanctions is that, concerned as Beijing is about Pyongyang’s behaviour, it does not want to push the regime so hard that it becomes significantly destabilised. The real reason China won’t exert economic pressure on North Korea From the vantage point of Chinese officials, this could result in even more unpredictable behaviour from North Korea, and/or the outside possibility of regime collapse, which would not be in Beijing’s interests: not least as it could lead to instability on the North Korea-China border and, ultimately, the potential emergence of a pro-US successor nation. Beijing is also concerned that Washington might even be thinking, seriously, about a pre-emptive strike on North Korea’s nuclear capabilities. The risks of this are great, and this is one reason why Wang asserted earlier this month that “China’s priority now is to flash the red light and apply the brakes on both [the US and North Korean] trains” to avoid a collision. North Korean nuclear threat at danger level, Tillerson tells Chinese hosts In China, a second key element of Tillerson’s trip was focused on trying to put bilateral relations on a more even keel after the early disruptions of the Trump presidency. He also sought to finalise the agenda with his Chinese hosts for a landmark meeting between presidents Xi Jinping ( 習近平 )and Donald Trump that is tentatively scheduled for next month. It is not just Trump, but also Tillerson himself, who has slammed Beijing in recent weeks. For instance, as Trump’s nominee for top US diplomat, Tillerson said in January that Beijing should “not be allowed access” to its new, artificial islands in the South China Sea. This was particularly sensitive for Beijing, given its high animus toward US sea and air manoeuvres near its borders. Watch: Rex Tillerson at confirmation hearings compares China to Russia in Crimea Underlying Trump’s own hawkish sentiment appears to be a conviction that China represents the primary threat to US interests globally. Yet, he has also acknowledged that Beijing can play a potentially constructive role in key policy areas, including North Korea. North Korea is behaving very badly. They have been "playing" the United States for years. China has done little to help! — Donald J. Trump (@realDonaldTrump) March 17, 2017 <!--//--><![CDATA[// ><!-- //--><!]]> In this context, the dealmaker in Trump’s political persona has surfaced with his comments that “everything is under negotiation” with Beijing , and it appears that he may ultimately be looking for a grand bargain extending beyond the security arena, to economics as well. Here, one specific measure he wants to see is China floating the yuan – last month, he called the Chinese the “ grand champions of currency manipulation ” – and asserts that China is keeping its exchange rate artificially low in order to secure export advantage. While this US rhetoric indicates tensions could rise further between Beijing and Washington in the coming months, it should be remembered that the Obama administration left bilateral ties in relatively positive shape, despite a shaky start after Xi took office. Then, Beijing’s foreign and military positions, and rhetoric, became significantly more pugnacious, but despite this – and numerous irritants that continue to this day, including alleged cyber attacks on US interests by Beijing – ties became generally cordial. This reflected, in part, the personal commitment of Obama and Xi. Both men recognised the priority of bilateral ties and, under Obama, Washington pursued a strategy with Beijing that promoted cooperation on softer issues like energy and climate change, while seeking constructive engagement on vexed harder issues like the South China Sea tensions. Meanwhile, Xi outlined, rhetorically at least, his desire to fundamentally redevelop a new type of great power relationship with the US to avoid the conflictual great power patterns of the past. This is an audacious goal, which still lacks any obvious definition, and it is not certain if the pledge remains in place, given the rhetorical bellicosity of Trump to China. Tillerson meets Xi Jinping, says Trump looking forward ‘to enhancing understanding’ Taken overall, Tillerson’s trip has underlined that Washington is looking for a new approach in the increasingly tense North Korea stand-off. Following consultations with Tokyo, Seoul and Beijing, the Trump team will now re-examine its options, and this topic is likely to be a key feature of the conversation between Trump and Xi at their meeting next month. Andrew Hammond is an associate at LSE IDEAS at the London School of Economics