Would that include moonbounce or HF ionospheric propagation for long-distance communications? I would imagine with a directional yagi and enough power, one could get through somewhere. Jammers cannot be omnidirectional. They have to have a node somewhere.
“Jammers cannot be omnidirectional.”
Some are (VHF/UHF), but to be more effective they scan and they scan fast. So, while 100% of the frequency is not jammed at all times, every frequency gets jammed at least a percentage and that percentage is enough to distrupt normal RF CW communications. This is why the military uses frequency hopping in the grass along with other techniques. It is unlikely that a jammer will hit the exact frequency as the transmitter at the same time. Getting jam proof communications is easy enough but we civilians do not have anything that does that.
Moon bounce is hard to accomplish all the time and is not a reliable communications technique. Plus, it can be jammed fairly easily.
I suspect we will have communications because if any enemy tries to jam us then we are no doubt in an all out war and we will take care of such transmissions.