President Donald Trump is discovering that the United States needs the world after all. During his 2016 campaign, he widely disparaged established US foreign policy. As President, he followed through, criticising allies in Europe for not pulling their weight. In Asia, he withdrew from multilateral forums and pushed back against China. As his campaign for re-election in 2020 gets under way, two key issues remain unresolved. Mr Trump has been pressing for a nuclear deal with North Korea and a renegotiated deal with Iran to replace the previous one. While an uncertain detente with North Korea is in place, Iran is at a tipping point.

America needs partners on both issues: China’s help with North Korea and Europe’s buy-in with Iran. Beijing, as President Xi Jinping made known at the G-20 summit, wants more than a cameo role in finding the sweet spot between Washington’s demands for complete denuclearisation and Pyongyang’s quest for sanctions relief. The Chinese Foreign Ministry revealed last Friday that Mr Xi pushed the US side to meet the North Koreans halfway when he met Mr Trump last month. The two sides are likely to pick up the threads at the Asean Regional Forum in two weeks. It is also conceivable that a good outcome over North Korea will spill over and help resolve the US-China trade dispute, which is threatening global growth.