The satellite images of bright strips of sand rising from turquoise waters and surrounded by an intricate network of support ships struck a nerve around the globe. The man-made islands vividly showed China’s slow-motion efforts to assert more control in the South China Sea but, more than that, they represented a direct challenge to the US which has long policed a waterway crucial to the global economy.

The images, released in April by the Washington-based think-tank the Center for Strategic and International Studies, have contributed to a distinctive shift in the American debate about China. Washington is starting to sound rattled. Not only is the US alarmed at Beijing’s ambitious foreign policy, whether in the South China Sea or the launch of its own international banks, but there is also a creeping fear that America is no longer sure about how to cope with Beijing’s growing influence.

“The consensus of 35 years and five administrations about how to deal with China is fraying so severely that we have lost confidence in the fundamental underpinnings of US-China policy,” says Frank Jannuzi, former Asia adviser to John Kerry and now head of the Mansfield Foundation, a Washington think-tank. “So people are beginning to look for a new approach.”