It should be Federal Law in which all State, County & City police agencies must attempt to use NON Lethal force to subdue or stop individuals. This would include alternative types of weapons and if guns have to be used, to incapacitate over kill as a goal.
In the event deadly force is used, then an exhaustive, federal inquiry to determine if other force was possible, and if so, then those involved in making that decision be brought up on criminal charges and suspended without pay until the matter is resolved.