Pretection against jamming...
I understand that a Part 15 AM station has no frequency protection as do licensed stations.
However, if someone starts and establishes a Part 15 Station, if not from an FCC perspective, then from a legal perspective, can he be protected from someone maliciously trying to interfere with his signal?
No. But you could always get in touch with the person running the station and make them stop. If you were REALLY established you could take them to court.
From what I understand, there is a general FCC rule that prohibits superfluous transmissions. I wonder if that could be used to shut down a Part 15 jammer?
I don't know if you could get the FCC to move on it. A court may be sympathetic, but getting into Federal district court is definitely a big time effort. State courts have concurrent jurisdiction on Federal law, but the big thing is getting the court to take the case, and then adequately establishing your case. You would have to teach the court a lot. I dunno about any other legal alternative, as radio is seen to be inherently interstate commerce and totally Federal province.
Contacting the jammer would be an important first step to either solve the problem or show that you have tried to solve this privately.