The basis of the American empire does not lie with its military machine, but with the US Dollar that is manipulated by the FED. The US via the FED is the NUMBER 1 manipulator of currencies as well as economies around the Globe.
Basic macroeconomics here:
If the FED decides to increase the money supply in the US via the interest rate options that it has, the value of foreign currencies AUTOMATICALLY adjusts to the new exchange rate. Hence, a country such as China that sells its products to the US, in this case, will have their products become more expensive overnight, since the value of the US dollar decreased and lost its purchasing power parity, resulting in a drop of exports that decreases China's GDP.
As you can see, this mechanism can theoretically be WEAPONIZED and has been used to attack China's exports to America in the past, in the explicit effort to make their items ARTIFICIALLY more expensive, and control their economic growth. However, China has responded to those moves with its centrally controlled monetary policy, whose aims were to maintain the existing US-China exchange rate to defend their exports to America.
Consequently, the accusation of China manipulating its currency is very misleading and is obviously propagandized in the US as unfair. Seeing that the US does the same currency manipulation, albeit, through the FED for its own geopolitical purposes, China is JUSTIFIED in its own monetary policy that is consistent with its own national interests.
The fact the US has currently resorted to tariffs exemplifies exactly what myself and other honest economists have said about Trump's trade war with China. It is the US who can't compete economically with China FAIRLY, despite its own currency manipulation and has to resort to tariffs to prop up its lack of economic competitiveness.