Nations adopt constitutions for the same reason that the ancient Mesopotamian lawgiver Hammurabi codified the laws of Babylon:to establish a supreme law of the land . Constitutions state the fundamental laws of society and are not meant to be easily revised . They are yardsticks by which activities of the government or the people are measured.A legislature can pass a law one year and repeal it the next,but amending the constitution is made deliberately much harder. In Sweden,constitutional amendments must be passed by two successive legislatures with a general election in between