When are police officers justified in pulling their guns?
The previous post is strong. I would only add that part of the police justification to brandishing their weapon has to be a clear identification that they are law officers. This must be clearly made to any suspect or individual who is confronted in that situation. Additionally, as police officers draw their weapons, it is standard practice to give orders as to how to deescalate the situation, indicating again that the use of firearms is defensive and preventive, as opposed to hostile and aggressive. There are times when using weapons is a necessary element of the situation, and in these cases, law officers make split second decisions to determine how to best end this situation before it spirals into something worse. In these settings, the justification of police firearm use is only to end conflict in a manner that features minimal damage or loss of life.
The policy varies slightly according to the state and local laws, but basically, officers are only permitted to brandish a weapon if they have a reasonable belief that it may be necessary to discharge it in defense of themselves or someone else. They are also never supposed to draw a weapon while off-duty, unless they or others are in immediate danger.