Modern military, policing and bureaucratic power over ordinary citizens’ daily lives pose special problems for accountability that earlier writers such as Locke or Montesquieu could not have foreseen. The custom and practice of the legal profession is an important part of people’s access to justice, whilst civil society is a term used to refer to the social institutions, communities and partnerships that form law’s political basis. The Catholic Church has the oldest continuously functioning legal system in the western world, predating the evolution of modern European civil law and common law systems. The Eastern Catholic Churches, which developed different disciplines and practices, are governed by the Code of Canons of the Eastern Churches. The canon law of the Catholic Church influenced the common law during the medieval period through its preservation of Roman law doctrine such as the presumption of innocence. Colour-coded map of the legal systems around the world, showing civil, common law, religious, customary and mixed legal systems.

• While laws are positive “is” statements (e.g. the fine for reversing on a highway is €500); law tells us what we “should” do.
• Public international law concerns relationships between sovereign nations.
• Rational individuals trade through bilateral contracts on open markets