Savannah vs. Georgia

The FPC is assisting a resident of Savannah, Georgia who is trying to get the city's restrictions on transporting firearms lifted. I think their prospects of success are pretty good: the Attorney General of Georgia filed an amicus curaie brief that unreservedly takes their side. 

The reason why he is on their side is straightforward. The state legislature of Georgia, its General Assembly, long ago passed a bill that was signed into law that forbids local governments from placing restrictions on firearms. That power is reserved to the state government only.

Savannah ignored that law and created its own regulation, which it is enforcing by having the city's police department issue fines and citations. As such, and as is increasingly normal for Democratic strongholds in red states, it is in open defiance of the state government. Unlike states vis-a-vis the Federal government, local governments are creatures of the state. They have no powers that are not granted by the legislature, and no sort of sovereignty of their own.

Nevertheless these localities are willing to court such lawsuits, as they only cost taxpayer money and might for a while allow them to get their way. If they ever manage to swing the state government, as has happened in Virginia, they'll change all the state laws to ensure they never lose again; but until then, this will have to do.