US president Donald Trump's address to the annual gathering of the United Nations general assembly in late September 2025 set a new low in international relations. Trump delivered a broadside attack on multilateralism - the effort to solve the world's problems through collective endeavour - as well as issues that have found common cause among rich and poor countries alike, such as climate change.

So where does this leave the work of organisations such as the G20? The body was set up by the G7 in 1999 in the wake of the Asian financial crisis. The purpose was to create a bigger grouping of countries to help manage the governance of the global economy.

The group now represents about 67% of the global population and about 85% of the global economy. But it's a strange beast: it is a self-selected group, which raises questions about its legitimacy. And it doesn't have a permanent secretariat, which makes its work cumbersome.

We asked four leading scholars for their answers. Given the changing global context, is the G20 still useful?

Caroline Southey, Founding Editor, Africa