Surface ships are of course visible to an enemy from miles away, many drones and aircraft are also easily detectable and certainly ground-based weapons such as missile launchers and interceptors can largely be seen by satellite.
This means any prepositioned assets put in place to deter or stop a Chinese amphibious assault on Taiwan are likely to be seen or known by attacking People’s Liberation Army forces.
Attack Submarines
But what about submarines? When considering these variables, it seems reasonable to entertain the thought that submarines and the realm of the undersea might be the best way for the U.S. and its allies to stop a Chinese invasion of Taiwan.
Ship and land-based sensors are now advanced to the point that it will be very difficult to position warships or even operate certain aircraft within striking distance of Taiwan which are not pretty easily seen by Chinese forces.
Therefore, China might be inclined to attempt a surprise attack when U.S. carriers and other visible assets are not within range. This, however, is where submarines and undersea drones come in.