"I think if we had a gun we would have been shot immediately." This is as good a place to start as any, at the logical limits of violent self-defense. The speaker is Andres Gutierrez of Nonviolent Peaceforce, a nonprofit organization that has engaged in peacekeeping work in troubled regions of the world for the last decade.
The call to pay close attention to race at this moment is a hot button issue with long simmering resentments now bubbling up to the surface and at a boil. The new awareness that sometime, while we were sleeping, police departments suited up like a military force, has awakened people to a perception of threat.
The military mission is to confront and kill a defined enemy. The peace officer has no enemies. His or her mission is to protect the community and everyone within it. No matter what crime they may have committed, all are entitled to the protections of the Constitution, the Bill of Rights and due process.