TL:DR: China has moved further up the value chain than we are comfortable with.
In the years before WWI, Britain and France looked at Germany's rapidly growing population and industrial capacity and what they saw gave them the willies. By a similar token, Germany watched as Russia industrialized and its population grew, and German war planners warned that Russia would be an unstoppable juggernaut if this were allowed to continue for one more generation.
Austria-Hungary to lesser extent did the same with Serbia, although Austrian obsession with Serbia was as much a personal thing with Konrad von Hotzendorf and his dream of marrying his mistress, Gina von Reininghausen.
TL:DR: China has moved further up the value chain than we are comfortable with.
In the years before WWI, Britain and France looked at Germany's rapidly growing population and industrial capacity and what they saw gave them the willies. By a similar token, Germany watched as Russia industrialized and its population grew, and German war planners warned that Russia would be an unstoppable juggernaut if this were allowed to continue for one more generation.
Austria-Hungary to lesser extent did the same with Serbia, although Austrian obsession with Serbia was as much a personal thing with Konrad von Hotzendorf and his dream of marrying his mistress, Gina von Reininghausen.