There is no reason for run-of-the-mill beat cops to have unlimited access to lethal weapons.

The vast majority of interactions with the public can be taken care of with non-lethal means, tasers, etc... (if any are even necessary).

Lethal weapons should be in a remote lock holster in their cruiser, and must be unlocked remotely by a supervisor on a per-case basis depending on the facts at hand (suspect's history, potential risk, etc...)

Maybe that's pie in the sky optimism, I don't know.