New Delhi, July 31 -- A new confrontation has started between the US and China: over humanoid robots. This week, America's Federal Communications Commission barred foreign-made advanced robotic devices from being imported into the US.

Though it didn't name any country, that Chinese robots are in Washington's crosshairs is not lost on Beijing. Its commerce ministry said escalating US restrictions "severely damage China-US economic and trade stability" and promised retaliatory action.

Beijing could bar supplies of rare earths to America and deny its companies market access. This could re-ignite an off-and-on trade war.

The US worry is that Chinese robots could act as spies, or worse, gang up as a fifth column. This echoes an anxiety over...