We are the government, law enforcement exists to protect government, therefore a cop is merely an extension of you. A cop can carry a firearm therefore you are in effect carrying a firearm. So, even if you will inevitably be banned from "owning" a firearm to be possessed by your physical person, your right to bear arms will not have been violated as your proxy agent in law enforcement will be upholding the right for you.
You=Government=Law Enforcement. So Law Enforcement with firearm=You bearing arms.
It's like science or sumfin.