What is Government? It is literally the controlling of people's behaviour. What does a government actually do? It makes rules, and rules are nothing but a collection of controls of people's behaviour. The rules are based on arbitrary policies, hence the root of the term "politics".
There is only one type of politics: Conservatism. Conservatism is the preferential allocation of more freedoms to one group of people, while selectively removing freedoms from another group of people. That's what Conservatism is, and that's what all governments do, and that's what Politics literally is. Nothing more.
What are the Police? The truth is hidden in plain sight: their name means that they are the ones who enforce the Policies of the Rulers who are in power at the time. They are literally the Rulers' thugs.
Their job is literally to restrict and control the freedoms of one group of people, while simultaneously allowing more freedoms for another group of people. Ostensibly, officially, they only act in strict accordance with the rules, but in practice they selectively and preferentially enforce the rules more or less within their broad discretionary powers, according to the unwritten and possibly also unspoken deeper Intent behind the current rulers' policies. For example, if the current rulers are clearly, obviously racist, but they haven't (yet?) codified their racism into written rules, the Police will use their latitude to enforce racism within the community.