The PLA cannot defend against that which they don’t know exists. In the Black World of DoD there are multiple capabilities that have never been unveiled. In fact, the SecDef does not even know all of the capabilities unless the managers in the Black World decide he has a need to know.
China’s satellites may all stop working. Their telephone and internet systems may cease operations. Their aircraft computers may decide to fly into the ground. Automobile and truck engines throughout entire regions may suddenly stop running. All radio communication could be disrupted. Submarines thought to be invulnerable will be located and quietly sunk.
In the financial world, a total embargo on Chinese exports coupled with the expropriation of all Chinese assets in the USA and the repudiation of any bonds they hold would cost them trillions.
That said, we have a spineless commie in the White House for at least two more years. I stand by my forecast that China will not miss this opportunity to conquer Taiwan, an island on which they have the most tenuous historical claim.
As in all other eras, weakness brings war.
IOW, RF magnetic field blast (a nuclear device detonated high enough above earth to create a massive magnetic field distortion) which would disable China’s satellites and their electronics on the ground. And financial and economic sabotage. Provided, as you have indirectly implied, we had a leadership chain in place capable of issuing the order.