Well the us has the biggest millitary in the world (and are also the biggest employer in the world) and have nuke and what not. But China make like everything for the us and if they cut that supply the us has a big disadvantage.
I guess when a majority of our toys and electronics supply gets cut we'll implode right? Fortunately for us most US based companies are bringing back manufacturing to the United States, if they can afford it, otherwise they're all just moving to Ireland.
If anything if we just stopped sending computer components to China they'd have to find someone else to trade with or their entire economy would collapse, so they don't control us as much as people like to believe.