I would submit that it's already begun.
I agree. Cyber attacks are acts of war. Russia and China are actively engaged and already know how to cripple our infrastructure and economy.
As Pope Francis stated not too long ago, we are already involved in a slow moving WW III. He may have socialistic tendencies but he is also smart enough to see and realize that many things are out of kilter and eventually will have to be fixed. Unfortunately more often than not it will take a war to fix it.