The problem with most hacking attacks is that the source of them is, fundamentally, unverifiable. Even if you can have an intelligent guess at the origin, you can't usually know.
But let's assume, for the sake of argument, that widespread malicious attacks against US companies, infrastructure and government are coming from China; there's plenty of evidence for it and it's a reasonable scenario. Furthermore, let's assume that the attackers in China are government agents or, at the very least, acting with the implicit consent of the Chinese government; this too is not unreasonable. Are we being slow motion Pearl Harbored?