Social contract vision
The power of police and their mandate to use force against citizens is justified under the social contract vision of society. This theory views the police use of force as necessary to maintain order and maximise collective good by maintaining a safe and workable society. Under social contract theory citizens are understood to voluntarily surrender some of their power and rights and delegate them to the state and to the police force. The police are seen as a politically neutral force that uses its powers to To make people obey (a law, the terms of an agreement, etc). Also: enforceability. the laws within the confines of a defined set of rules.
The social contract theory of policing informs mainstream views of policing, which see police as a protective force against crime and social disorder. Given the widespread belief in the social contract theory of police and the partisan nature of media reporting, the general public is often uncritically supportive of police behaviour even where such behaviour involves high levels of force and coercion. Police violence against protesters will often be seen as legitimate even where it goes beyond the bounds of reasonable force.
As mentioned above, however, there are many examples of repressive policing of protests both in Australia and other western countries which suggest that the social contract theory is not adequate in explaining the nature of the police role in relation to political protests.