occupying a facility illegally, though sometimes violence has been known to occur. Often there is an expectation to be attacked or even beaten by the authorities. Protesters often undergo training in advance on how to react to arrest or to attack. Civil disobedience is usually defined as pertaining to a citizen's relation to the state and its laws, as distinguished from a constitutional impasse, in which two public agencies, especially two equally sovereign branches of government, conflict. For instance, if the head of government of a country were to refuse to enforce a decision of that country's highest court, it would not be civil disobedience, since the head of government would act in his or her capacity as public official rather than private citizen. This definition is disputed by Thoreau's political philosophy on the conscience vs. the collective. The person is the final judge of right and wrong. More than this, since only people act, only a person can act unjustly. When the government knocks on the door, it is a person in the form of a postman or tax collector whose hand hits the wood. Before Thoreau's imprisonment, when a confused taxman had wondered aloud about how to handle his refusal to pay, Thoreau had advised, "Resign". If a man chose to be an agent of injustice, then Thoreau insisted on confronting him with the fact that he was making a choice. He admits that government may express the will of the majority but it may also express nothing more than the will of elite politicians. Even a good form of government is "liable to be abused and perverted before the people can act through it". If a government did express the voice of most people, this would not compel the obedience of those who disagree with what is said. The majority may be powerful but it is not necessarily right. In his 1971 book, A Theory of Justice, John Rawls described civil disobedience as "a public, non-violent, conscientious yet political act contrary to law usually done with the aim of bringing about change in the law or policies of the government". Ronald Dworkin held that there are three types of civil disobedience: "Integrity-based" civil disobedience occurs when a citizen disobeys a law they feel is immoral, as in the case of abolitionists disobeying the fugitive slave laws by refusing to turn over escaped slaves to authorities. "Justice-based" civil