Police are often called upon to deal with "crowd control" where the crowd has become "worked up" as the result of a speech given by a public speaker. Police can often "sense" when the speaker is provoking the crowd to take direct action that can potentially result in property loss and injury. They have a duty to stop such a situation. However, their "discretion" in such a situation must be governed or limited by: The availability of "back up" officers to help control the crowd if things get ugly. The 1st Amendment rights of the speaker and the right of the crowd to hear his ideas. Their own political views Whether they have been called in "on overtime