People should be free to do whatever they can and wish to do. But that does not give license to people to do such things that cause harm to others. Since it would be too inefficient for each of us to individually protect himself or herself from harm by others, it is prudent to collectively create a mechanism that provides “policing services” that prevent anyone from causing harm to others, and in case harm is caused, to provide a means for the redressal of the harm and the punishment of the culprit. This fundamental function of providing policing services is the government’s proper role. Thus the proper role of the government must be limited to restraining people from harming others but not to forcing people into doing particular things.
In other words, the government’s job is solely to protect the negative right of every person, namely the right to be unharmed by others. Of course, there has to be a mechanism for determining what actions are harmful to others. The design of the mechanism that determine the rules — the rules of just conduct — has to be specified by a set of meta-rules. These meta-rules we call the constitution.