Leaders from the world’s leading countries are gathering for the Group of 20 summit in Buenos Aires, Argentina, to discuss issues including development, infrastructure and investment. But as the meeting starts, those themes seem like afterthoughts, overshadowed by contentious matters such as the US-China trade dispute, the Ukraine conflict, tensions between the US and Europe, and how the Saudi crown prince, alleged to have ordered the killing of Jamal Khashoggi, is received by world leaders