Back in the 1990, the air force rushed two prototype JSTARS to Kuwait before the Gulf War. The aircraft could detect and track every ground vehicle in the theater of operations. Technology has advanced considerably over the past two decades. I've heard that JSTAR class detection has been miniaturized to the point that it can fit into a much smaller airframe, such as Global Hawk and other large stealthy UAVs.

China would fair very badly in a shooting war with us. Not only would their military be mauled, but the economic fallout would be far more devastating. If the US and our allies stopped trading with them, their economy would collapse overnight. This is something I don't see the Chinese willing to risk.