After al-Qaida attacked the twin towers in New York 20 years ago, the U.S., Europe, China, Russia and even Iran rallied around a rare common cause: To topple a Taliban regime in Kabul that had made Afghanistan a base for international terrorism.

Now that unlikely group of geopolitical rivals find their interests aligned once more, only this time to see those same Taliban leaders restore order in a nation of 38 million whose economic collapse could trigger destabilizing humanitarian and refugee crises.

In the weeks since Kabul fell to Taliban fighters on Aug. 16, world leaders one after another have called for international cooperation even as they jockey to gain influence in the great power vacuum that the U.S. departure has left behind.