I thought this topic might deserve it's own thread.
Police agencies have policies governing their Use of Force and Responses to Resistance that come under scrutiny from time to time. Most of them indicate that if the subject does "A" then the officer can respond with "A".
The Subject's "A" might include one or several examples of typical low level resistance that don't normally pose a significant threat of serious boduily injury or death the the officer or others.
The Officer's "A" is intended to parallel the subject's resistance and be appropriate, justified and reasonable. It should allow for the officer's authority and tactical need for control if neccessary for safety but it should not be overly oppressive, aggressive, etc.
The officer's "A" includes a predictiable risk of bodily harm to the subject based upon an accepted reasonable level of peril related to their degree of resistance. For example, if the subject simply refuses to leave a bar parking lot after closing, striking him with a baton might not be a reasonable option under normal circumstances.